As filed with the Securities and Exchange Commission on September 19, 2025.

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-4

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Churchill Capital Corp IX

(Exact name of registrant as specified in its charter)

For Co-Registrants, see “Table of Co-Registrants” on the following page.

640 Fifth Avenue, 14th Floor

New York, NY 10019

Tel: (212) 380-7500

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Jay Taragin

Chief Financial Officer

c/o Churchill Capital Corp IX

640 Fifth Avenue, 14th Floor

New York, NY 10019

Tel: (212) 380-7500

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Approximate date of commencement of proposed sale of the securities to the public: As soon as practicable after this registration statement becomes effective and upon completion of the merger.

If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box. ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

If applicable, place an ☒ in the box to designate the appropriate rule provision relied upon in conducting this transaction:

Exchange Act Rule 13e-4(i) (Cross-Border Issuer Tender Offer) ☐

Exchange Act Rule 14d-1(d) (Cross-Border Third-Party Tender Offer) ☐

* Prior to the consummation of the Business Combination described herein, the Registrant intends to effect a deregistration under Section 206 of the Companies Act (As Revised) of the Cayman Islands and a domestication under Section 388 of the Delaware General Corporation Law, pursuant to which the Registrant’s jurisdiction of incorporation will be changed from the Cayman Islands to the State of Delaware. All securities being registered will be issued by Churchill Capital Corp IX (after its domestication as a corporation incorporated in the State of Delaware), the continuing entity following the Domestication, which will be renamed “PlusAI Holdings, Inc.”

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the U.S. Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

TABLE OF CO-REGISTRANTS

Plus Automation, Inc.

3315 Scott Boulevard, Suite 300

Santa Clara, CA 95054

Tel: (408) 508-4758

Steven J. Spinner

Plus Automation, Inc.

3315 Scott Boulevard, Suite 300

Santa Clara, CA 95054

Tel: (408) 508-4758

EXPLANATORY NOTE

This proxy statement/prospectus relates to an Agreement and Plan of Merger and Reorganization, dated as of June 5, 2025 (as amended by Amendment No.1 dated September 8, 2025 and Amendment No.2 dated September 18, 2025 and as may be further amended, modified, supplemented or waived from time to time, the “Merger Agreement”), by and among Churchill Capital Corp IX, a Cayman Islands exempted company (“CCIX”), AL Merger Sub I, Inc., a Delaware corporation and direct, wholly owned subsidiary of CCIX (“Merger Sub I”), AL Merger Sub II, LLC, a Delaware limited liability company and a direct, wholly owned subsidiary of CCIX (“Merger Sub II”, and, together with Merger Sub I, “Merger Subs”) and Plus Automation, Inc., a Delaware corporation (“PlusAI”), a copy of which is attached to this proxy statement/prospectus as an annex thereto.

The Merger Agreement, among other things and subject to the terms and conditions contained therein, provides for (a) the transfer of the registration of CCIX by way of continuation from the Cayman Islands to the State of Delaware (the “Domestication”), and (b) following the Domestication, the merger of Merger Sub I with and into PlusAI, with PlusAI continuing as the surviving corporation, and immediately thereafter, such surviving corporation merging with and into Merger Sub II, with Merger Sub II continuing as the surviving entity and as a wholly owned subsidiary of CCIX (collectively, the “Merger,” and, together with the Domestication and other transactions contemplated by the Merger Agreement and the related agreements, the “Transactions” or the “business combination”). Following the consummation of the business combination, CCIX will change its name to “PlusAI Holdings, Inc.” We refer to the new public entity following the consummation of the business combination as the “Post-Closing Company.”

This proxy statement/prospectus serves as:

On May 14, 2025, the parties submitted a request to the SEC’s Office of Chief Accountant in the Division of Corporation Finance (the “Division”) seeking confirmation that the Staff of the Division’s Office of Chief Accountant would permit the inclusion of audited consolidated financial statements of PlusAI for the six months ended June 30, 2025 as a substitute for audited financial statements from the seven months ended July 31, 2023 that would be required to be included in this proxy statement/prospectus under SEC rules. On May 28, 2025, the Staff of the Division’s Office of Chief Accountant permitted the parties’ request. Accordingly, this proxy statement/prospectus includes audited financial statements of PlusAI for the five months ended December 31, 2023, the year ended December 31, 2024, and the six months ended June 30, 2025.

CHURCHILL CAPITAL CORP IX

640 Fifth Avenue, 14th Floor

New York, NY 10019

Dear Churchill Capital Corp IX Shareholders,

On behalf of Churchill Capital Corp IX, a Cayman Islands exempted company (“CCIX,” “we” or “our”) board of directors (the “CCIX Board”), we cordially invite you to an extraordinary general meeting in lieu of an annual general meeting (the “extraordinary general meeting”) of shareholders of CCIX, to be held via live webcast at a.m. Eastern Time, on , 2025. The physical location of the extraordinary general meeting will be Willkie Farr & Gallagher LLP at 787 Seventh Avenue, New York, New York 10019. The extraordinary general meeting can be accessed by visiting , where you will be able to listen to the meeting live, ask questions and vote during the meeting.

On June 5, 2025, CCIX entered into an Agreement and Plan of Merger and Reorganization (as amended by Amendment No.1 dated September 8, 2025 and Amendment No.2 dated September 18, 2025 and as may be further amended, modified, supplemented or waived from time to time, the “Merger Agreement”), by and among CCIX, AL Merger Sub I, Inc., a Delaware corporation and direct, wholly owned Subsidiary of CCIX (“Merger Sub I”), AL Merger Sub II, LLC, a Delaware limited liability company and a direct, wholly owned Subsidiary of CCIX (“Merger Sub II”, and, together with Merger Sub I, “Merger Subs”) and Plus Automation, Inc., a Delaware corporation (“PlusAI”), a copy of which is attached to the accompanying proxy statement/prospectus as Annex A, which, among other things, provides for (a) the transfer of the registration of CCIX by way of continuation from the Cayman Islands to the State of Delaware (the “Domestication”), and (b) following the Domestication, the merger of Merger Sub I with and into PlusAI, with PlusAI continuing as the surviving corporation, and immediately thereafter, such surviving corporation merging with and into Merger Sub II, with Merger Sub II continuing as the surviving entity and as a wholly owned subsidiary of CCIX (the “Merger,” and, together with the Domestication and other transactions contemplated by the Merger Agreement and the related agreements, the “Transactions” or the “business combination”). In connection with the business combination, CCIX will change its name to “PlusAI Holdings, Inc.” We refer to the new public entity following the consummation of the business combination as the “Post-Closing Company.”

Subject to the terms and conditions of the Merger Agreement, the value of the aggregate consideration to be paid to PlusAI stockholders and holders of PlusAI SAFEs, vested PlusAI RSUs, vested PlusAI options and vested PlusAI warrants will be (1) (a) $1,200,000,000 plus (b) the amount of any net proceeds raised by PlusAI prior to the consummation of the Transactions (the “Closing”) through certain sales of its equity securities in a bona fide equity financing transaction (subject to certain limitations, a “Permitted Equity Financing”) minus (c) the amount if any by which the PlusAI transaction expenses exceed $12,000,000 (the sum of (a), (b) and (c), the “Equity Value”), which consideration will be paid entirely in shares of common stock, par value $0.0001 per share, of the Post-Closing Company (“Post-Closing Company common stock”), in an amount equal to $10.00 per share, in addition to (2) the contingent right to receive up to an aggregate of 15,000,000 shares of Post-Closing Company common stock, which will be issued to certain eligible holders of pre-Closing securities of PlusAI during the five-year period following the Closing (the “Earnout Period”), in three equal, separate tranches (such shares, the “Earnout Shares”), upon the satisfaction of certain price targets, which will be based upon (a) the volume-weighted average sale price of one share of Post-Closing Company Class A common stock as quoted on the Global Market tier of the Nasdaq Stock Market (“Nasdaq”) or the exchange on which the shares of Post-Closing Company Class A common stock are then traded, for any 15 trading days within any 180 consecutive trading day period within the Earnout Period or (b) if the Post-Closing Company undergoes a Change in Control, the price per share received by shareholders of the Post-Closing Company in such Change in Control transaction (or if consideration is not received by shareholders of the Post-Closing Company, the price per share implied by such transaction). At the Effective Time, each share of PlusAI common stock issued and outstanding immediately prior to the Closing (other than Excluded Shares and Dissenting Shares) will be automatically surrendered and exchanged for the right to receive a number of shares of Post-Closing Company common stock equal to the Exchange Ratio, which is based on the Per Share Equity Value (calculated in accordance with the Merger Agreement). Subject to the assumptions described herein, as of the date of this proxy statement/prospectus, we estimate that the Exchange Ratio will be approximately shares of Post-Closing Company common stock for each issued and outstanding share of PlusAI common stock; see the section entitled “Proposal No. 1 — The Business Combination Proposal — General — Structure of the Transactions.”

At the extraordinary general meeting, CCIX shareholders will be asked to consider and vote upon:

The full text of the resolution to be passed is as follows:

“RESOLVED, as an ordinary resolution, that the business combination proposal (as such term is defined in CCIX's proxy statement/prospectus dated , 2025), be approved, ratified and confirmed in all respects.”

The full text of the resolution to be passed is as follows:

“RESOLVED, as a special resolution, that the domestication proposal (as such term is defined in CCIX’s proxy statement/prospectus dated , 2025), be approved, ratified and confirmed in all respects.”

The full text of the resolution to be passed is as follows:

“RESOLVED, as a special resolution, that the organizational documents proposal (as such terms are defined in CCIX’s proxy statement/prospectus dated , 2025) be approved and adopted.”

The full text of the resolution to be passed is as follows:

“RESOLVED, as an ordinary resolution, that on an advisory non-binding basis, the advisory organizational documents proposal (as such term is defined in CCIX’s proxy statement/prospectus dated , 2025), be approved and adopted.”

The full text of the resolution to be passed is as follows:

“RESOLVED, as an ordinary resolution, that the stock issuance proposal (as such term is defined in CCIX’s proxy statement/prospectus dated , 2025) be approved in all respects.”

The full text of the resolution to be passed is as follows:

“RESOLVED, as an ordinary resolution, that the incentive plan proposal (as such term is defined in CCIX’s proxy statement/prospectus dated , 2025) be approved in all respects.”

The full text of the resolution to be passed is as follows:

“RESOLVED, as an ordinary resolution, that the ESPP proposal (as such term is defined in CCIX’s proxy statement/prospectus dated , 2025) be approved in all respects.”

The full text of the resolution to be passed is as follows:

“RESOLVED, as an ordinary resolution, on a non-binding advisory basis, that the director election proposal (as such term is defined in CCIX's proxy statement/prospectus dated , 2025) be approved in all respects.”

The full text of the resolution to be passed is as follows:

“RESOLVED, as an ordinary resolution, that the adjournment proposal (as such term is defined in CCIX’s proxy statement/prospectus dated , 2025) be approved in all respects.”

Each of these proposals are more fully described in the accompanying proxy statement/prospectus, which we encourage you to read carefully and in its entirety before voting. Only CCIX shareholders of record at the close of business on , 2025 are entitled to notice of the extraordinary general meeting and to vote and have their votes counted at the extraordinary general meeting and any adjournments or postponements thereof.

Consummation of the business combination is conditioned on the approval of each of the condition precedent proposals. If any of those proposals are not approved at the extraordinary general meeting (or any adjournment or postponement thereof), then unless certain conditions in the Merger Agreement are waived by the applicable parties to the Merger Agreement, the Merger Agreement may be terminated and the business combination may not be consummated.

All CCIX shareholders are cordially invited to attend the extraordinary general meeting, and we are providing the accompanying proxy statement/prospectus and proxy card in connection with the solicitation of proxies to be voted at the extraordinary general meeting (or any adjournment or postponement thereof). To ensure your representation at the extraordinary general meeting, however, you are urged to complete, sign, date and return the enclosed proxy card as soon as possible and no later than the time of the extraordinary general meeting or, if the meeting is adjourned, the time for holding such adjourned meeting. If your shares of CCIX’s shares are held in an account at a brokerage firm or bank, you must instruct your broker or bank on how to vote your shares or, if you wish to attend the extraordinary general meeting and vote, obtain a proxy card from your broker or bank.

CCIX Class A Ordinary Shares are currently listed on Nasdaq under the symbol “CCIX.” In connection with the Transactions, CCIX intends to apply to have Post-Closing Company Class A common stock listed on Nasdaq under the symbol “PLS,” and it will change its name to “PlusAI Holdings, Inc.”

Pursuant to CCIX’s current articles of association, a holder of CCIX Class A Ordinary Shares sold in CCIX’s initial public offering (whether they were purchased in CCIX’s initial public offering or thereafter in the open market) (“CCIX public shares”) may demand that CCIX redeem such shares for cash if the business combination is consummated (“redemption rights”). Such redemption rights are not available to our Sponsor, directors or officers. Eligible holders of CCIX public shares will be entitled to receive cash for these shares only if they demand that CCIX redeem their CCIX public shares for cash no later than the second business day prior to the initially scheduled vote on the business combination proposal or such later date as our directors may determine (the “Redemption Deadline”) by delivering their shares and requesting in writing that CCIX redeem such CCIX public shares for cash to Continental Stock Transfer & Trust Company, CCIX’s transfer agent. If the business combination is not completed, the CCIX public shares will not be redeemed. If an eligible holder of CCIX public shares properly exercises their redemption rights and the business combination is consummated, CCIX will redeem such shares for cash in an amount equal to their pro rata portion of the funds in the trust account holding the proceeds from CCIX’s initial public offering (the

“trust account”), calculated as of two business days prior to the consummation of the business combination net of certain permitted withdrawals.

Notwithstanding the foregoing, a holder of CCIX public shares, together with any affiliate of such holder or any other person with whom such holder is acting in concert or as a “group” (as defined in Section 13(d)(3) of the Exchange Act), will be restricted from seeking redemption with respect to more than 15% of the CCIX public shares. Accordingly, all CCIX public shares in excess of 15% held by a CCIX public shareholder, together with any affiliate of such holder or any other person with whom such holder is acting in concert or as a “group,” will not be redeemed without the prior consent of our directors. Such redemption rights are also not available to our Sponsor, officers or directors.

CCIX is an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”) and has elected to comply with certain reduced public company reporting requirements.

CCIX (including as the Post-Closing Company) will remain an emerging growth company until the earlier of: (1) the last day of the fiscal year (a) following May 6, 2029, the fifth anniversary of the CCIX IPO, (b) in which CCIX has total annual gross revenue of at least $1,235,000,000, or (c) in which CCIX is deemed to be a large accelerated filer, which means the market value of CCIX Class A Ordinary Shares held by non-affiliates exceeds $700,000,000 as of the end of the prior June 30th; and (2) the date on which CCIX has issued more than $1,000,000,000 in nonconvertible debt during the prior three-year period. References herein to “emerging growth company” shall have the meaning associated with it in the JOBS Act.

The accompanying proxy statement/prospectus provides you with detailed information about the business combination and other matters to be considered at the extraordinary general meeting. We encourage you to carefully read the entire document, including the Annexes attached to the accompanying proxy statement/prospectus. You should also carefully consider the risk factors described in “Risk Factors” beginning on page 60.

Your vote is important regardless of the number of CCIX Ordinary Shares you own. Whether you plan to attend the extraordinary general meeting or not, please sign, date and return the enclosed proxy card as soon as possible, and no later than the time of the extraordinary general meeting (or any adjournment thereof) in the envelope provided. If your CCIX Class A Ordinary Shares are held in “street name” or are in a margin or similar account, you should contact your broker to ensure that votes related to the shares you beneficially own are properly counted.

The business combination described in the accompanying proxy statement/prospectus has not been approved or disapproved by the SEC or any state securities commission nor has the SEC or any state securities commission passed upon the merits or fairness of the business combination, or passed upon the accuracy or adequacy of the disclosure in the accompanying proxy statement/prospectus. Any representation to the contrary is a criminal offense.

Thank you for your participation. We look forward to your continued support.

, 2025

IF YOU RETURN YOUR PROXY CARD WITHOUT AN INDICATION OF HOW YOU WISH TO VOTE, YOUR CCIX SHARES WILL BE VOTED AT THE DISCRETION OF YOUR NOMINATED PROXY.

TO EXERCISE YOUR REDEMPTION RIGHTS, YOU MUST ELECT TO HAVE CCIX REDEEM YOUR CCIX PUBLIC SHARES FOR A PRO RATA PORTION OF THE FUNDS HELD IN THE TRUST ACCOUNT (NET OF CERTAIN PERMITTED WITHDRAWALS) AND TENDER SUCH SHARES TO CCIX’S TRANSFER AGENT AT LEAST TWO BUSINESS DAYS PRIOR TO THE INITIALLY SCHEDULED VOTE AT THE EXTRAORDINARY GENERAL MEETING. YOU MAY TENDER YOUR CCIX PUBLIC SHARES BY EITHER DELIVERING YOUR SHARE CERTIFICATE TO THE TRANSFER AGENT OR BY DELIVERING SUCH SHARES ELECTRONICALLY USING THE DEPOSITORY TRUST COMPANY’S DWAC (DEPOSIT AND WITHDRAWAL AT CUSTODIAN) SYSTEM. IF THE BUSINESS COMBINATION IS NOT COMPLETED, THEN SUCH CCIX PUBLIC SHARES WILL NOT BE REDEEMED FOR CASH. IF YOU HOLD CCIX PUBLIC SHARES IN STREET NAME, YOU WILL NEED TO INSTRUCT THE ACCOUNT EXECUTIVE AT YOUR BANK OR BROKER TO WITHDRAW SUCH SHARES FROM YOUR ACCOUNT IN ORDER TO EXERCISE YOUR REDEMPTION RIGHTS. PLEASE SEE THE SECTION ENTITLED “EXTRAORDINARY GENERAL MEETING OF CCIX SHAREHOLDERS — REDEMPTION RIGHTS” FOR MORE SPECIFIC INSTRUCTIONS.

Immediately following the Redemption Deadline, a public shareholder that makes an election to redeem its CCIX public shares (an “Election”) may withdraw its Election with respect to all or a portion of its CCIX public shares for which it previously submitted an Election (an “Election Reversal”).

TO MAKE AN ELECTION REVERSAL WITH RESPECT TO YOUR CCIX PUBLIC SHARES, YOU MUST SUBMIT A WRITTEN REQUEST TO THE TRANSFER AGENT, AFTER 5:00 P.M. EASTERN TIME ON , 2025, THE DATE THAT IS TWO BUSINESS DAYS PRIOR TO THE SCHEDULED VOTE AT THE EXTRAORDINARY GENERAL MEETING, AND PRIOR TO THE SCHEDULED VOTE AT THE EXTRAORDINARY GENERAL MEETING, THAT THE ELECTION TO REDEEM YOUR CCIX PUBLIC SHARES BE REVERSED, INCLUDING THE LEGAL NAME, PHONE NUMBER, AND ADDRESS OF THE BENEFICIAL OWNER OF THE SHARES FOR WHICH REVERSAL IS REQUESTED AND THE NUMBER OR PERCENTAGE OF SHARES FOR WHICH REVERSAL IS REQUESTED. IF YOU HOLD THE SHARES IN STREET NAME, YOU WILL NEED TO INSTRUCT THE ACCOUNT EXECUTIVE AT YOUR BANK OR BROKER TO REQUEST REVERSAL OF THE ELECTION TO REDEEM AT THE TRANSFER AGENT.

The accompanying proxy statement/prospectus is dated , 2025 and is first being mailed to CCIX shareholders on or about , 2025.

ADDITIONAL INFORMATION

No person is authorized to give any information or to make any representation with respect to the matters that this proxy statement/prospectus describes other than those contained in this proxy statement/prospectus, and, if given or made, the information or representation must not be relied upon as having been authorized by CCIX or PlusAI. This proxy statement/prospectus does not constitute an offer to sell or a solicitation of an offer to buy securities or a solicitation of a proxy in any jurisdiction where, or to any person to whom, it is unlawful to make such an offer or a solicitation. Neither the delivery of this proxy statement/prospectus nor any distribution of securities made under this proxy statement/prospectus will, under any circumstances, create an implication that there has been no change in the affairs of CCIX or PlusAI since the date of this proxy statement/prospectus or that any information contained herein is correct as of any time subsequent to such date.

The accompanying proxy statement/prospectus incorporates important information that is not included in or delivered with this proxy statement/prospectus. This information is available for you to review through the SEC’s website at www.sec.gov.

You may request copies of this proxy statement/prospectus or other information concerning CCIX, without charge, by written request directed to:

Churchill Capital Corp IX

640 Fifth Avenue, 14th Floor

New York, NY 10019
Attention: Jay Taragin, Chief Financial Officer

Email: info@churchillcapitalcorp.com

or:

Morrow Sodali LLC

333 Ludlow Street, 5th Floor, South Tower

Stamford, CT 06902
Call Toll-Free (800) 662-5200 or (203) 658-9400
Email: ALCC.info@investor.morrowsodali.com

In order for you to receive timely delivery of the documents in advance of the extraordinary general meeting of CCIX to be held on , 2025, you must request the information no later than five business days prior to the date of the extraordinary general meeting.

CHURCHILL CAPITAL CORP IX
640 Fifth Avenue, 14th Floor
New York, NY 10019

NOTICE OF EXTRAORDINARY GENERAL MEETING OF SHAREHOLDERS
TO BE HELD ON , 2025

TO THE SHAREHOLDERS OF CHURCHILL CAPITAL CORP IX

NOTICE IS HEREBY GIVEN that an extraordinary general meeting (the “extraordinary general meeting”) of shareholders of Churchill Capital Corp IX, a Cayman Islands exempted company (“CCIX,” “we” or “our”), will be held via live webcast at a.m. Eastern Time, on , 2025. The extraordinary general meeting can be accessed by visiting where you will be able to listen to the meeting live, ask questions and vote during the meeting. The physical location of the extraordinary general meeting will be Willkie Farr & Gallagher LLP at 787 Seventh Avenue, New York, New York 10019.

On behalf of CCIX’s board of directors (the “CCIX Board”), you are cordially invited to attend the extraordinary general meeting, to conduct the following business items:

Each of these proposals and the business combination are more fully described in this proxy statement/prospectus, which we encourage you to read carefully and in its entirety before voting. Only CCIX shareholders of record at the close of business on , 2025 are entitled to notice of the extraordinary general meeting and to vote and have their votes counted at the extraordinary general meeting and any adjournments or postponements thereof.

After careful consideration, the CCIX Board has unanimously determined that the business combination proposal, domestication proposal, organizational documents proposal, advisory organizational documents proposal, stock issuance proposal, incentive plan proposal, ESPP proposal, director election proposal and, if necessary, the adjournment proposal are fair to, and in the best interests of, CCIX and its shareholders and unanimously recommends that you vote or give instruction to vote “FOR” the business combination proposal, “FOR” the domestication proposal, “FOR” the organizational documents proposal, “FOR” the advisory organizational documents proposal, “FOR” the stock issuance proposal, “FOR” the ESPP proposal, “FOR” each of the director nominees named in the director election proposal and, if presented, “FOR” the adjournment proposal. When you consider the CCIX Board’s recommendation of these proposals, you should keep in mind that our directors and officers, as well as Churchill Sponsor IX, LLC, our sponsor (the “Sponsor”), have interests in the Transactions that are different from, or in addition to, the interests of CCIX shareholders generally. Please see the section entitled “Proposal No. 1 — The Business Combination Proposal — Interests of Certain CCIX Persons in the Business Combination” for additional information. The CCIX Board was aware of and considered these interests, among other matters, including the fairness opinion of Ocean Tomo, in evaluating and negotiating the Transactions and in recommending to CCIX shareholders that they vote in favor of the proposals presented at the extraordinary general meeting.

Consummation of the business combination is conditioned on the approval of each of the other condition precedent proposals. If any of those proposals are not approved at the extraordinary general meeting (or any adjournment or postponement thereof), then unless certain conditions in the Merger Agreement are waived by the applicable parties to the Merger Agreement, the Merger Agreement may be terminated and the business combination may not be consummated.

Pursuant to CCIX’s current articles of association, a holder of CCIX Class A Ordinary Shares sold in CCIX’s initial public offering (whether they were purchased in CCIX’s initial public offering or thereafter in the open market) (“CCIX public shares”) may demand that CCIX redeem such shares for cash if the business combination is consummated (“redemption rights”). Such redemption rights are not available to our Sponsor, directors or officers. Eligible holders of CCIX public shares will be entitled to receive cash for these shares only if they demand that CCIX redeem their CCIX public shares for cash no later than the second business day prior to the initially scheduled vote on the business combination proposal or such later date as our directors may determine (the “Redemption Deadline”) by delivering their shares and requesting in writing that CCIX redeem such CCIX public shares for cash to Continental Stock Transfer & Trust Company, CCIX’s transfer agent. If the business combination is not completed, the CCIX public shares will not be redeemed. If an eligible holder of CCIX public shares properly exercises their redemption rights and the business combination is consummated, CCIX will redeem such shares for cash in an amount equal to their pro rata portion of the funds in the trust account holding the proceeds from CCIX’s initial public offering (the “trust account”), calculated as of two business days prior to the consummation of the business combination and net of certain permitted withdrawals.

Notwithstanding the foregoing, a holder of CCIX public shares, together with any affiliate of such holder or any other person with whom such holder is acting in concert or as a “group” (as defined in Section 13(d)(3) of the Exchange Act), will be restricted from seeking redemption with respect to more than 15% of the CCIX public shares. Accordingly, all CCIX public shares in excess of 15% held by a CCIX public shareholder, together with any affiliate of such holder or any other person with whom such holder is acting in concert or as a “group,” will not be redeemed without the prior consent of our directors. Such redemption rights are also not available to our Sponsor, officers or directors.

All CCIX shareholders are cordially invited to attend the extraordinary general meeting and we are providing this proxy statement/prospectus and proxy card in connection with the solicitation of proxies to be voted at the extraordinary general meeting (or any adjournment or postponement thereof). To ensure your representation at the extraordinary general meeting, however, you are urged to complete, sign, date and return the enclosed proxy card as soon as possible and no later than the time of the extraordinary general meeting or, if the meeting is adjourned, the time for holding such adjourned meeting. If your CCIX shares are held in an account at a brokerage firm or bank, you must instruct your broker or bank on how to vote your shares or, if you wish to attend the extraordinary general meeting and vote, obtain a proxy card from your broker or bank.

Your vote is important regardless of the number of CCIX’s shares you own. Whether you plan to attend the extraordinary general meeting or not, please sign, date and return the enclosed proxy card as soon as possible, and no later than the time of the extraordinary general meeting or, if the meeting is adjourned, the time for holding such adjourned meeting, in the envelope provided. If your CCIX shares are held in “street name” or are in a margin or similar account, you should contact your broker to ensure that votes related to the shares you beneficially own are properly counted.

Thank you for your participation. We look forward to your continued support.

, 2025

IF YOU RETURN YOUR PROXY CARD WITHOUT AN INDICATION OF HOW YOU WISH TO VOTE, YOUR SHARES OF CCIX PUBLIC SHARES WILL BE VOTED AT THE DISCRETION OF YOUR PROXY

TO EXERCISE YOUR REDEMPTION RIGHTS, YOU MUST ELECT TO HAVE CCIX REDEEM YOUR CCIX PUBLIC SHARES FOR A PRO RATA PORTION OF THE FUNDS HELD IN THE TRUST ACCOUNT (NET OF PERMITTED WITHDRAWALS) AND TENDER SUCH SHARES TO CCIX’S TRANSFER AGENT AT LEAST TWO BUSINESS DAYS PRIOR TO THE INITIALLY SCHEDULED VOTE AT THE EXTRAORDINARY GENERAL MEETING. YOU MAY TENDER YOUR CCIX PUBLIC SHARES BY EITHER DELIVERING YOUR SHARE CERTIFICATE TO THE TRANSFER AGENT OR BY DELIVERING SUCH SHARES ELECTRONICALLY USING THE DEPOSITORY TRUST COMPANY’S DWAC (DEPOSIT AND WITHDRAWAL AT CUSTODIAN) SYSTEM. IF THE BUSINESS COMBINATION IS NOT COMPLETED, THEN SUCH CCIX PUBLIC SHARES WILL NOT BE REDEEMED FOR CASH. IF YOU HOLD CCIX PUBLIC SHARES IN STREET NAME, YOU WILL NEED TO INSTRUCT THE ACCOUNT EXECUTIVE AT YOUR BANK OR BROKER TO WITHDRAW SUCH SHARES FROM YOUR ACCOUNT IN ORDER TO EXERCISE YOUR REDEMPTION RIGHTS. PLEASE SEE THE SECTION ENTITLED “EXTRAORDINARY GENERAL MEETING OF CCIX SHAREHOLDERS — REDEMPTION RIGHTS” FOR MORE SPECIFIC INSTRUCTIONS.

Immediately following the Redemption Deadline, a public shareholder that makes an election to redeem its CCIX public shares (an “Election”) may withdraw its Election with respect to all or a portion of its CCIX public shares for which it previously submitted an Election (an “Election Reversal”).

TO MAKE AN ELECTION REVERSAL WITH RESPECT TO YOUR CCIX PUBLIC SHARES, YOU MUST SUBMIT A WRITTEN REQUEST TO THE TRANSFER AGENT, AFTER 5:00 P.M. EASTERN TIME ON , 2025, THE DATE THAT IS TWO BUSINESS DAYS PRIOR TO THE SCHEDULED VOTE AT THE EXTRAORDINARY GENERAL MEETING, AND PRIOR TO THE SCHEDULED VOTE AT THE EXTRAORDINARY GENERAL MEETING, THAT THE ELECTION TO REDEEM YOUR CCIX PUBLIC SHARES BE REVERSED, INCLUDING THE LEGAL NAME, PHONE NUMBER, AND ADDRESS OF THE BENEFICIAL OWNER OF THE SHARES FOR WHICH REVERSAL IS REQUESTED AND THE NUMBER OR PERCENTAGE OF SHARES FOR WHICH REVERSAL IS REQUESTED. IF YOU HOLD THE SHARES IN STREET NAME, YOU WILL NEED TO INSTRUCT THE ACCOUNT EXECUTIVE AT YOUR BANK OR BROKER TO REQUEST REVERSAL OF THE ELECTION TO REDEEM AT THE TRANSFER AGENT.

TABLE OF CONTENTS

FREQUENTLY USED TERMS

Unless otherwise stated in this proxy statement/prospectus or the context otherwise requires, references to:

“$100 Million Available Closing SPAC Cash Scenario” are to the scenario that illustrates the consummation of the Transactions with $100,000,000 of Available Closing SPAC Cash as a result of redemptions by CCIX public shareholders.

“2017 Plan” are to the 2017 Share Plan of PlusAI, duly adopted by PlusAI, Inc. as approved by the Board of Directors of PlusAI, Inc. in 2017 and assumed by PlusAI in connection with the Restructuring.

“2021 Plan” are to the 2021 Share Incentive Plan of PlusAI, duly adopted by PlusAI as approved by the PlusAI Board in 2021.

“25% Redemption Scenario” or “25% Redemptions” are to the scenario that assumes 25% of CCIX public shareholders exercise their redemption rights.

“50% Redemption Scenario” or “50% Redemptions” are to the scenario that assumes 50% of CCIX public shareholders exercise their redemption rights.

“Amendment No. 1” are to that certain amendment of the Merger Agreement dated September 8, 2025.

“Amendment No. 2” are to that certain amendment of the Merger Agreement dated September 18, 2025.

“Available Closing SPAC Cash” are to all amounts in the trust account (after reduction for the aggregate amount of payments required to be made in connection with any valid CCIX public stockholder redemptions of CCIX public shares and any permitted withdrawals, but before payment of any CCIX or PlusAI transaction expenses and repayment of any Sponsor loans, if any), plus the net proceeds of any incremental financing raised by CCIX or PlusAI in connection with the Transactions, including any Permitted Equity Financing.

“business combination” are to the Merger, together with the other transactions contemplated by the Merger Agreement. The “business combination” will constitute an initial business combination under the terms of the CCIX current articles of association.

“CCIX” are to Churchill Capital Corp IX. Prior to the Domestication, CCIX is an exempted company incorporated under the laws of the Cayman Islands. Following the Domestication, subject to shareholder approval, CCIX will be a corporation incorporated under the laws of the State of Delaware named “PlusAI Holdings, Inc.”

“CCIX Board” are to the board of directors of CCIX.

“CCIX Class A Common Stock” are to the shares of Class A common stock of CCIX, par value $0.0001 per share, immediately upon the Domestication.

“CCIX Class A Ordinary Shares” are to the Class A ordinary shares of CCIX, par value $0.0001 per share.

“CCIX Class B Ordinary Shares” are to the Class B ordinary shares of CCIX, par value $0.0001 per share.

“CCIX current articles of association” are to CCIX’s amended and restated memorandum and articles of association in effect as of the date of this proxy statement/prospectus.

“CCIX Founder Shares” are to CCIX Class B Ordinary Shares initially purchased by the Sponsor and the Class A Ordinary Shares that will be issued upon the conversion of such CCIX Class B Ordinary Shares prior to the Domestication.

“CCIX IPO” means the initial public offering of 28,750,000 CCIX public units, including 3,750,000 CCIX public units under the underwriters’ over- allotment option, which closed on May 6, 2024.

“CCIX Net Tangible Asset closing condition” means the closing condition in the Merger Agreement that requires CCIX to have at least $5,000,001 of net tangible assets as of the Closing.

“CCIX Ordinary Shares” collectively, are to the CCIX Class A Ordinary Shares and the CCIX Class B Ordinary Shares.

“CCIX private placement shares” are to the Class A Ordinary Shares included within the CCIX private placement units.

“CCIX private placement units” are to the units issued to the Sponsor in the private placement that occurred simultaneously with the closing of the CCIX IPO.

“CCIX private placement warrants” are to the warrants (i.e., one-quarter warrant for each Class A Ordinary Share) included within the CCIX private placement units.

“CCIX public shares” are to shares of Class A Ordinary Shares sold as part of the CCIX public units sold in the CCIX IPO.

“CCIX public shareholders” are to the holders of CCIX public shares. CCIX public shareholders includes the Sponsor and the CCIX officers or directors to the extent that the Sponsor and/or CCIX’s officers or directors hold CCIX public shares, provided that each of their status as a CCIX public shareholder will only exist with respect to such CCIX public shares.

“CCIX public units” are to the CCIX public units sold in the CCIX IPO, all of which (other than as of the date hereof) have been separated into CCIX public shares and CCIX public warrants.

“CCIX public warrants” are to the warrants (i.e., one-quarter warrant for each Class A Ordinary Share) sold as part of the CCIX public units sold in the CCIX IPO.

“CCIX record date” are to the close of business on , 2025.

“CCIX Units” are to the CCIX public units and CCIX private placement units.

“CCIX Warrants” are to the CCIX public warrants and CCIX private placement warrants.

“Change in Control” are to (1) a purchase, sale, exchange, business combination or other transaction (including a merger or consolidation of the Post-Closing Company with or into any other corporation or other entity) in which the equity securities of the Post-Closing Company, its successor, or the surviving entity of such business combination or other transaction are not registered under the Exchange Act or listed or quoted for trading on a national securities exchange, (2) a sale, lease, exchange or other transfer (including a merger) in one transaction or a series of related transactions of assets representing 50% or more of the value of the Post-Closing Company’s assets (including other subsidiaries of the Post-Closing Company) to a third party that is not an affiliate of the Sponsor (or a group of third parties that are not affiliates of the Sponsor), (3) the transfer to or acquisition by (whether by tender offer, merger, consolidation, division or other similar transaction), in one transaction or a series of related transactions, a person or entity or group of affiliated persons or entities (other than an underwriter pursuant to an offering), of the Post-Closing Company’s voting securities if, after such transfer or acquisition, such person, entity or group of affiliated persons or entities would beneficially own (as defined in Rule 13d-3 promulgated under the Exchange Act) more than 50% of the outstanding voting securities of the Post-Closing Company (it being understood that, for the purposes of this clause (4), a bona fide equity financing shall not be considered a Change in Control) or (5) a merger, consolidation or other business combination with or involving the Post-Closing Company (or any subsidiary or subsidiaries that alone or together represent 50% or more of the value of the Post-Closing Company’s assets) that results in the stockholders of the Post-Closing Company immediately before the consummation of such transaction or series of related transactions

holding, directly or indirectly, less than 50% of the voting power of the Post-Closing Company (or such subsidiary or subsidiaries) or of any successor or surviving entity thereof or of any acquiring entity (or parent thereof), as applicable, immediately following the consummation of such transaction or series of related transactions.

“Citi” are to Citigroup Global Markets Inc.

“Closing” are to the closing of the business combination.

“Closing Date” are to the date the Closing occurs.

“Code” are to the U.S. Internal Revenue Code of 1986, as amended.

“Companies Act” are to the Companies Act (As Revised) of the Cayman Islands.

“completion window” are to the period following the completion of the CCIX IPO at the end of which, if CCIX has not completed an initial business combination, it will redeem 100% of the CCIX public shares at a per share price, payable in cash, equal to the aggregate amount then on deposit in the trust account, including interest (net of permitted withdrawals and less up to $100,000 of such accrued interest to pay dissolution expenses), divided by the number of then outstanding CCIX public shares, subject to applicable law and certain conditions. The completion window ends on May 6, 2026 (or by August 6, 2026 if CCIX has executed a letter of intent, agreement in principle or definitive agreement for an initial business combination by May 6, 2026).

“condition precedent proposal” are to, collectively, the business combination proposal, the domestication proposal, the organizational documents proposal, the stock issuance proposal, the incentive plan proposal, the ESPP proposal and the director election proposal.

“Conversion” are to the conversion immediately prior to the Closing of (1) all shares of PlusAI preferred stock into shares of PlusAI common stock in accordance with the terms of PlusAI’s current certificate of incorporation and (2) all PlusAI SAFEs into shares of PlusAI common stock in accordance with the terms thereof, in each case pursuant to the terms of the Merger Agreement.

“Court” are to the Delaware Court of Chancery.

“DGCL” are to the Delaware General Corporation Law, as amended.

“Dissenting Shares” are to the shares of PlusAI capital stock that are issued and outstanding immediately prior to the Effective Time and that are held by stockholders (including beneficial owners) that neither voted in favor of the Merger nor consented thereto in writing and that have demanded properly in writing appraisal or dissenters’ rights for such shares of PlusAI capital stock in accordance with the DGCL or who shall have validly exercised a redemption right for such shares of PlusAI capital stock under PlusAI’s current certificate of incorporation.

“Domestication” are to the deregistration of CCIX as an exempted company registered under the laws of the Cayman Islands and registration by way of continuation and domestication of CCIX into a Delaware corporation under the applicable provisions of the CCIX current articles of association, the Companies Act and the DGCL. The term “Domestication” includes all matters and necessary or ancillary changes in order to effect such domestication, including the adoption of the Proposed Certificate of Incorporation (a form of which is attached to this proxy statement/prospectus as Annex B) consistent with the DGCL and changing the name of the registered agent and the address of the registered office of CCIX.

“domestication proposal” are to the proposal to be considered at the extraordinary general meeting to approve by special resolution the Domestication.

“Earnout Period” are to the time period commencing on the Closing Date and ending on the earlier of (1) the five-year anniversary of the Closing Date and (2) a Change in Control.

“Earnout Shares” are to up to an aggregate of 15,000,000 shares of Post-Closing Company common stock that will be issued to Eligible PlusAI Equityholders upon the occurrence of an Earnout Triggering Event during the Earnout Period.

“Earnout Triggering Event I” are to the earliest of the following to occur during the Earnout Period: (1) the date on which the VWAP of one share of Post-Closing Company Class A common stock is greater than or equal to $12.00 per share for 15 trading days within any 180 consecutive trading day period or (2) a Change in Control of the Post-Closing Company pursuant to which stockholders of Post-Closing Company Class A common stock have the right to receive consideration implying a price per share greater than or equal to $12.00 or, in the case of a Change in Control where the holders of Post-Closing Company Class A common stock do not receive consideration, the price per share of Post-Closing Company Class A common stock implied by such transaction (as determined in good faith by the board of directors of the Post-Closing Company) is greater than or equal to $12.00.

“Earnout Triggering Event II” are to the earliest of the following to occur during the Earnout Period: (1) the date on which the VWAP of one share of Post-Closing Company Class A common stock is greater than or equal to $14.00 per share for 15 trading days within any 180 consecutive trading day period or (2) a Change in Control of the Post-Closing Company pursuant to which stockholders of Post-Closing Company Class A common stock have the right to receive consideration implying a price per share greater than or equal to $14.00 or, in the case of a Change in Control where the holders of Post-Closing Company Class A common stock do not receive consideration, the price per share of Post-Closing Company Class A common stock implied by such transaction (as determined in good faith by the board of directors of the Post-Closing Company) is greater than or equal to $14.00.

“Earnout Triggering Event III” are to the earliest of the following to occur during the Earnout Period: (1) the date on which the closing VWAP of one share of Post-Closing Company Class A common stock is greater than or equal to $16.00 per share for 15 trading days within any 180 consecutive trading day period or (2) a Change in Control of the Post-Closing Company pursuant to which stockholders of Post-Closing Company Class A common stock have the right to receive consideration implying a price per share greater than or equal to $16.00 or, in the case of a Change in Control where the holders of Post-Closing Company Class A common stock do not receive consideration, the price per share of Post-Closing Company Class A common stock implied by such transaction (as determined in good faith by the board of directors of the Post-Closing Company) is greater than or equal to $16.00.

“Earnout Triggering Events” are to Earnout Triggering Event I, Earnout Triggering Event II and Earnout Triggering Event III, collectively.

“Effective Time” are to the date and time that the merger of Merger Sub I with and into PlusAI becomes effective pursuant to the terms of the Merger Agreement.

“Eligible PlusAI Equityholder” are to all persons that hold one or more shares of PlusAI common stock as of immediately prior to the Effective Time (after giving effect to the Conversion).

“Equity Value” are to the sum of (1) $1,200,000,000 plus (2) the amount of any net proceeds raised by PlusAI prior to the consummation of the Transactions through a Permitted Equity Financing minus (3) the amount, if any, by which the aggregate PlusAI transaction expenses exceeds $12,000,000.

“ESPP” are to the proposed PlusAI Holdings, Inc. 2025 Employee Stock Purchase Plan, a copy of which is attached to this proxy statement/prospectus as Annex E.

“Exchange Act” are to the Securities Exchange Act of 1934, as amended.

“Exchange Ratio” are to the quotient, rounded to the nearest thousandth (0.001), obtained by dividing (1) the Per Share Equity Value by (2) $10.00.

“Excluded Shares” are to the shares of PlusAI capital stock held in PlusAI’s treasury or owned by CCIX, Merger Sub I or PlusAI immediately prior to the Effective Time.

“existing registration rights agreement” are to the Registration Rights Agreement, dated May 1, 2024, between CCIX and certain other security holders named therein, in connection with the CCIX IPO.

“extraordinary general meeting” are to the extraordinary general meeting of shareholders of CCIX, to be held via live webcast at      a.m. Eastern Time, on           , 2025. The physical location of the extraordinary general meeting will be Willkie Farr & Gallagher LLP at 787 Seventh Avenue, New York, New York 10019.

“GAAP” are to accounting principles generally accepted in the United States of America.

“HSR Act” are to the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended.

“Incentive Plan” are to the proposed PlusAI Holdings Inc. 2025 Equity Incentive Plan, a copy of which is attached to this proxy statement/prospectus as Annex D.

“Insiders” are to Michael Klein, Jay Taragin, Stephen Murphy, William Sherman, and Paul Lapping.

“IPO Promissory Note” are to that certain Promissory Note, dated as of December 18, 2023, made by CCIX to the Sponsor, for the principal sum of up to $600,000.

“IRS” are to the Internal Revenue Service.

“Lockup Release Trigger Event I” are to the date on which the VWAP of the Post-Closing Company Class A common stock on the Nasdaq, or such other securities exchange where Post-Closing Company Class A common stock is primarily listed or quoted, equals or exceeds $12.00 for any 15 trading days within any 180 consecutive trading day period.

“Lockup Release Trigger Event II” are to the date on which the VWAP of the Post-Closing Company Class A common stock on the Nasdaq, or such other securities exchange where Post-Closing Company Class A common stock is primarily listed or quoted, equals or exceeds $14.00 for 15 trading days within any 360 consecutive trading day period.

“Lockup Release Triggering Events” are to Lockup Release Trigger Event I and Lockup Release Trigger Event II, collectively.

“Maximum Redemption Scenario” or “Maximum Redemptions” are to the scenario that illustrates the largest number of redemptions by CCIX public shareholders that can occur while satisfying the CCIX Net Tangible Asset closing condition under the Merger Agreement.

“Merger” are to the merger of Merger Sub I with and into PlusAI, with PlusAI continuing as the surviving corporation and, immediately thereafter, the merger of the surviving company with and into Merger Sub II, with Merger Sub II continuing as the surviving entity and a wholly owned subsidiary of CCIX, collectively.

“Merger Agreement” are to that certain Agreement and Plan of Merger and Reorganization, dated as of June 5, 2025, by and among CCIX, PlusAI, Merger Sub I, and Merger Sub II, as amended by Amendment No. 1 and Amendment No. 2 and as the same may be further amended, modified, supplemented or waived from time to time.

“Merger Sub I” are to AL Merger Sub I, Inc., a Delaware corporation and a direct, wholly owned subsidiary of CCIX.

“Merger Sub II” are to AL Merger Sub II, LLC, a Delaware limited liability company and a direct, wholly owned subsidiary of CCIX.

“MKA” are to M. Klein Associates, Inc., a New York corporation.

“No Redemption Scenario” or “No Redemptions” are to the scenario that illustrates the consummation of the Transactions with no CCIX public shareholders exercising their redemption rights.

“Nasdaq” are to the Nasdaq Stock Market.

“ordinary resolution” are to a resolution (a) passed by a simple majority of such holders of outstanding CCIX Ordinary Shares as, being entitled to do so, vote in person or, where proxies are allowed, by proxy at a general meeting of the CCIX and where a poll is taken regard shall be had in computing a majority to the number of votes to which each holder of outstanding CCIX Ordinary Shares is entitled; or (b) approved in writing by all of the holders of outstanding CCIX Ordinary Shares entitled to vote at a general meeting of the CCIX (or such lower threshold as may be allowed under the Companies Act from time to time) in one or more instruments each signed by one or more of such holders of outstanding CCIX Ordinary Shares and the effective date of the resolution so adopted shall be the date on which the instrument, or the last of such instruments, if more than one, is executed.

“Penny Options” are to common stock options granted to third parties with the exercise price equal to the par value of the underlying share and fully vested at issuance.

“Per Share Equity Value” are to the quotient, rounded to the nearest $0.01, obtained by dividing (1) the sum of (a) the Equity Value plus (b) the aggregate exercise price of all PlusAI options to the extent outstanding and vested as of immediately prior to the Effective Time by (2) the PlusAI Total Shares.

“Permitted Equity Financing” are to certain sales by PlusAI of its equity securities in a bona fide equity financing transaction not to exceed $50,000,000 in the aggregate, unless otherwise agreed in writing between CCIX and PlusAI, subject to certain limitations set forth in the Merger Agreement.

“permitted withdrawals” are to amounts withdrawn by CCIX from account trust account to (1) fund CCIX’s working capital requirements, subject to an annual limit of $1,000,000, and (2) pay CCIX’s taxes, notwithstanding the $1,000,000 annual limitation applicable to working capital withdrawals; all permitted withdrawals may only be made from interest and not from the principal held in the trust account.

“PlusAI” are to Plus Automation, Inc., a Delaware corporation, prior to the Effective Time (or, as expressly stated in this proxy statement/prospectus or the context otherwise requires, the Post-Closing Company).

“PlusAI Board” are to the board of directors of PlusAI.

“PlusAI capital stock” are to PlusAI common stock and PlusAI preferred stock.

“PlusAI Class A common stock” are to PlusAI’s Class A common stock, par value $0.0001 per share.

“PlusAI Class B common stock” are to PlusAI’s Class B common stock, par value $0.0001 per share.

“PlusAI common stock” are to PlusAI’s Class A common stock and Class B common stock.

“PlusAI LV preferred stock” are to PlusAI Series A-3-X preferred stock, PlusAI Series A-4 preferred stock and PlusAI Series B-X preferred stock, collectively and shares of PlusAI common stock resulting from the conversion thereof.

“PlusAI options” are to all issued and outstanding options to purchase or otherwise acquire shares of PlusAI common stock (whether or not vested) held by any person, including PlusAI stock options granted under the 2017 Plan and 2021 Plan.

“PlusAI preferred stock” are to, collectively, PlusAI Series A-1 preferred stock, PlusAI Series A-2 preferred stock, PlusAI Series A-3-X preferred stock, PlusAI Series A-4 preferred stock, PlusAI Series A-4-X preferred stock, PlusAI Series B preferred stock, PlusAI Series B-X preferred stock, and PlusAI Series C preferred stock.

“PlusAI stockholder” means holder of PlusAI preferred stock, which includes holders of PlusAI preferred stock, PlusAI common stock and PlusAI SAFEs, that, pursuant to the Conversion, are converted to PlusAI common stock immediately prior to the Merger.

“PlusAI record date” are to the close of business on            , 2025.

“PlusAI RSUs” are to all issued and outstanding restricted stock units corresponding to shares of PlusAI common stock (whether or not vested) held by any person, including PlusAI RSUs granted under the 2017 Plan and 2021 Plan.

“PlusAI SAFEs” are to the simple agreements for future equity between PlusAI and the investors party thereto.

“PlusAI Series A-1 preferred stock” are to PlusAI’s Series A-1 preferred stock, par value $0.0001 per share.

“PlusAI Series A-2 preferred stock” are to PlusAI’s Series A-2 preferred stock, par value $0.0001 per share.

“PlusAI Series A-3-X preferred stock” are to PlusAI’s Series A-3-X preferred stock, par value $0.0001 per share.

“PlusAI Series A-4 preferred stock” are to PlusAI’s Series A-4 preferred stock, par value $0.0001 per share.

“PlusAI Series A-4-X preferred stock” are to PlusAI’s Series A-4-X preferred stock, par value $0.0001 per share.

“PlusAI Series B preferred stock” are to PlusAI’s Series B preferred stock, par value $0.0001 per share.

“PlusAI Series B-X preferred stock” are to PlusAI’s Series B-X preferred stock, par value $0.0001 per share.

“PlusAI Series C preferred stock” are to PlusAI’s Series C preferred stock, par value $0.0001 per share.

“PlusAI Total Shares” are to the sum of (1) the aggregate number of issued and outstanding shares of PlusAI common stock as of immediately prior to the Effective Time after giving effect to the Conversion, calculated on an as-converted to PlusAI common stock basis, (2) the aggregate number of shares of PlusAI common stock issuable upon the exercise of all PlusAI options to the extent outstanding and vested as of immediately prior to the Effective Time, (3) the aggregate number of shares of PlusAI common stock issuable upon the settlement of PlusAI RSUs outstanding as of immediately prior to the Effective Time and that will vest in full solely as a result of the consummation of the Merger, and (4) the aggregate number of shares of PlusAI common stock issuable as of immediately prior to the Effective Time upon the exercise of all PlusAI warrants (on a net issuance basis) to the extent outstanding and vested as of immediately prior to the Effective Time, calculated on an as-converted to PlusAI common stock basis.

“PlusAI Voting and Support Agreements” are to those certain Voting and Support Agreements by and among CCIX, PlusAI and certain PlusAI stockholders.

“PlusAI warrants” are to all issued and outstanding warrants exercisable for PlusAI common stock or PlusAI preferred stock (whether or not vested) held by any person.

“PlusAI’s current bylaws” are to PlusAI’s bylaws in effect as of the date of this proxy statement/prospectus.

“PlusAI’s current certificate of incorporation” are to PlusAI’s amended and restated certificate of incorporation in effect as of the date of this proxy statement/prospectus.

“Post-Closing Company” are to PlusAI Holdings, Inc., the public entity (formerly named Churchill Capital Corp IX) following the consummation of the business combination.

“Post-Closing Company assumed warrants” are to all issued and outstanding warrants to purchase shares of Post-Closing Company Class A common stock immediately following the Closing of the Merger as a result of the assumption by the Post-Closing Company of PlusAI warrants in accordance with the terms of the Merger Agreement.

“Post-Closing Company Board” are to the board of directors of the Post-Closing Company.

“Post-Closing Company Class A common stock” are to shares of Class A common stock, par value $0.0001 per share, of the Post-Closing Company.

“Post-Closing Company Class B common stock” are to shares of Class B common stock, par value $0.0001 per share, of the Post-Closing Company.

“Post-Closing Company common stock” are to shares of Post-Closing Class A common stock and Post-Closing Class B common stock.

“Post-Closing Company options” are to all issued and outstanding options to purchase shares of Post-Closing Company common stock, including PlusAI options assumed by the Post-Closing Company that become an option to purchase shares of Post-Closing Company common stock in accordance with the terms of the Merger Agreement.

“Post-Closing Company preferred stock” are to the Post-Closing Company’s preferred stock, par value $0.0001 per share.

“Post-Closing Company public warrants” are to all issued and outstanding warrants to purchase shares of Post-Closing Company Class A common stock immediately following the Closing of the Merger as a result of the conversion of CCIX public warrants in connection with the Domestication and the Merger in accordance with the terms of the Merger Agreement.

“Post-Closing Company RSUs” are to the Post-Closing Company’s restricted stock units.

“Post-Closing Company warrants” are to the Post-Closing Company public warrants and Post-Closing Company assumed warrants.

“pro forma” are to giving pro forma effect to the Transactions and the other related events contemplated by the Merger Agreement.

“Proposed Bylaws” are to the proposed amended and restated bylaws of the Post-Closing Company in the form attached as Annex C.

“Proposed Certificate of Incorporation” are to the proposed second amended and restated certificate of incorporation of the Post-Closing Company in the form attached hereto as Annex B. CCIX will be renamed PlusAI Holdings, Inc. pursuant thereto.

“redemption rights” are to the rights of eligible CCIX public shareholders’ demand that CCIX redeem their CCIX public shares for cash in an amount equal to their pro rata portion of the funds held in the trust account, net of certain permitted withdrawals, if the business combination is consummated.

“Registration Rights Agreement” are to the Amended and Restated Registration Rights Agreement, to be effective as of the Closing Date, by and among the Post-Closing Company, certain CCIX shareholders and certain PlusAI stockholders.

“Restructuring” are to the series of transactions consummated on July 31, 2023 by PlusAI Corp and all of its then shareholders which ultimately resulted in the divestiture of its operating entity in the People’s Republic of China, Plus PRC Holdings Ltd.

“Securities Act” are to the Securities Act of 1933, as amended.

“SPAC Material Adverse Effect” are to, with respect to CCIX, a material adverse effect on: (1) the ability of CCIX, Merger Sub I, or Merger Sub II to enter into the Merger Agreement or any Transaction Agreement and perform its respective obligations thereunder or consummate the Transactions or (2) the business, condition (financial or otherwise), assets, liabilities or operations of CCIX; provided, however, that none of the following shall be deemed to constitute, alone or in combination, or be taken into account in the determination of whether, there has been or will be a SPAC Material Adverse Effect under this clause (3): (a) any change in applicable laws or GAAP or any interpretation thereof, (b) any change in interest rates or economic, political, business, financial, commodity, currently or market conditions generally, (c) any actions taken or not taken by CCIX, or such other changes or events, in each case, which (i) PlusAI has consented in writing or (ii) are required by the Merger Agreement and (d) the announcement or the execution of the Merger Agreement, the pendency or consummation of the Merger or the performance of the Merger Agreement.

“special resolution” means a special resolution of CCIX passed in accordance with the Companies Act, being a resolution: (1) passed by a majority of not less than two-thirds, other than with respect to amending either of Articles 22.5 or 27(d) of the CCIX current articles of association (except where such amendment is proposed in respect of the consummation of the business combination) where such majority shall be at least 90%, of such holders of outstanding CCIX Ordinary Shares as, being entitled to do so, vote in person or, where proxies are allowed, by proxy at a general meeting of CCIX of which notice specifying the intention to propose the resolution as a special resolution has been duly given and where a poll is taken regard shall be had in computing a majority to the number of votes to which each holder of outstanding CCIX Ordinary Shares is entitled; or (2) approved in writing by all of the holders of outstanding CCIX Ordinary Shares entitled to vote at a general meeting of CCIX (or such lower threshold as may be allowed under the Companies Act from time to time) in one or more instruments each signed by one or more of such holder of outstanding CCIX Ordinary Shares and the effective date of the special resolution so adopted shall be the date on which the instrument or the last of such instruments, if more than one, is executed.

“Sponsor Agreement” are to the Amended and Restated Letter Agreement, dated as of June 5, 2025, as amended by the Sponsor Agreement Amendment, by and among CCIX, the Sponsor and the Insiders.

“Sponsor Agreement Amendment” are to the Amendment to the Sponsor Agreement, dated as of September 18, 2025, by and among CCIX, the Sponsor and the Insiders.

“Sponsor Lockup” are to the contractual restrictions on transfers of CCIX Founder Shares and CCIX private placement units by the Sponsor and Insiders, generally prohibiting transfers for six months after Closing (in the case of the CCIX Founder Shares) and 30 days after Closing (in the case of the CCIX private placement units), subject to limited exceptions.

“SuperDrive” is to PlusAI’s flagship product, a proprietary AI‑based software platform that enables L4 autonomous driving for heavy‑duty trucks.

“Transaction Agreements” or “related agreements” are to the Merger Agreement, the Sponsor Agreement, the Registration Rights Agreement, the PlusAI Voting and Support Agreements, the Proposed Bylaws and the Proposed Certificate of Incorporation and all of the agreements, documents, instruments and certificates entered into in connection with such documents and any and all exhibits and schedules thereto.

“Transactions” are to the Merger, together with the other transactions contemplated by the Merger Agreement and the related agreements.

“trust account” are to the trust account of CCIX that holds the proceeds from the CCIX IPO.

“Working Capital Loans” are to the unsecured promissory note to potentially be issued by CCIX to the Sponsor in an aggregate principal amount of up to $1,500,000.

“VWAP”, for any security as of any trading day, are to the dollar volume-weighted average price for such security on the principal securities exchange or securities market on which such security is then traded during such trading day beginning at 9:30:01 a.m., New York time, and ending at 4:00:00 p.m., New York time, as reported by Bloomberg through its “HP” function (set to weighted average). If the foregoing does not apply, “VWAP” shall mean the dollar volume-weighted average price of such security in the over-the-counter market on the electronic bulletin board for such security during such trading day beginning at 9:30:01 a.m., New York time, and ending at 4:00:00 p.m., New York time, as reported by Bloomberg. If no dollar volume-weighted average price is reported for such security by Bloomberg for such hours, “VWAP” shall mean the average of the highest closing bid price and the lowest closing ask price of any of the market makers for such security as reported by OTC Markets Group Inc for such trading day. If the VWAP cannot be calculated for such security on such date(s) on any of the foregoing bases, the VWAP of such security on such shall be the fair market value per share on such day as reasonably determined by the Post-Closing Company Board (including for the avoidance of doubt a duly authorized committee thereof).

QUESTIONS AND ANSWERS ABOUT THE BUSINESS COMBINATION

The questions and answers below highlight only selected information from this proxy statement/prospectus and only briefly address some commonly asked questions about the extraordinary general meeting and the proposals to be presented at the extraordinary general meeting, including with respect to the business combination proposal. The following questions and answers do not include all the information that is important to CCIX shareholders, who are urged to read carefully this entire proxy statement/prospectus, including the Annexes and the other documents referred to herein, to fully understand the business combination.

Questions and Answers for CCIX shareholders about the extraordinary general meeting and the business combination

This proxy statement/prospectus and its Annexes contain important information about the business combination proposal and the other matters and proposals to be acted upon at the extraordinary general meeting. You should read this proxy statement/prospectus and its Annexes carefully and in their entirety.

Your vote is important. You are encouraged to submit your proxy card as soon as possible after carefully reviewing this proxy statement/prospectus, its Annexes and the other documents referred to herein.

CCIX will hold the extraordinary general meeting to consider and vote upon these proposals. This proxy statement/prospectus contains important information about the proposals to be acted upon at the extraordinary general meeting. Shareholders should read it carefully, including its Annexes.

Consummation of the business combination is conditioned on the approval of each of the condition precedent proposals (as defined above). If any of those proposals are not approved at the extraordinary general meeting (or any adjournment or postponement thereof), then unless certain conditions in the Merger Agreement are waived by the applicable parties to the Merger Agreement, the Merger Agreement may be terminated and the business combination may not be consummated.

The vote of CCIX shareholders is important. CCIX shareholders are encouraged to vote as soon as possible after carefully reviewing this proxy statement/prospectus.

On May 6, 2024, CCIX completed its initial public offering (the “CCIX IPO”) of CCIX public units at a price of $10.00 per unit, consisting of one share of CCIX Class A Ordinary Shares and one quarter of one warrant, raising total gross proceeds of approximately $287,500,000. Simultaneously with the closing of the CCIX IPO and pursuant to a private placement of CCIX private placement units at a price of $10.00 per unit (the “CCIX Private Placement”), raising total gross proceeds of approximately $7,250,000. Since the CCIX IPO and the CCIX Private Placement, CCIX’s activity has been limited to the evaluation of initial business combination candidates.

PlusAI was founded in 2016 by entrepreneurs with deep expertise in engineering, artificial intelligence, and machine learning. PlusAI adopted an AI‑native approach to autonomy early on, using advanced AI models in place of traditional rule-based code to enable scalable and adaptive self-driving technology. Our four founders have collectively founded and scaled six other technology companies, bringing a track record of successful execution in technology markets.

PlusAI is developing autonomous driving intelligence at global scale to create lasting value for the commercial trucking ecosystem by enhancing safety and lowering the cost of freight transportation. PlusAI develops its flagship product, SuperDrive, in partnership with OEMs with a planned commercial deployment in 2027. SuperDrive is designed to improve safety, efficiency, and cost-effectiveness for commercial fleets.

The CCIX Board conducted extensive due diligence on PlusAI’s business, financial condition, management team, and future growth prospects in executing upon and achieving its business plan. The CCIX Board considered the results of the diligence review, including the expertise of PlusAI’s management team, the large expected market desire for autonomous vehicles, the government policy and funding support being made available to accelerate development of autonomous vehicles, PlusAI’s existing OEM partnerships, as well as its AI powered virtual driver software. As a result, CCIX believes that the business combination will provide CCIX shareholders with an opportunity to participate in the ownership of a company with growth potential. Please see the section entitled “Proposal No. 1 — The Business Combination Proposal — The CCIX Board’s Reasons for Approval of the Transactions.”

The following summarizes the pro forma shares of the Post-Closing Company common stock issued and outstanding immediately after the business combination and Transactions on an issued and outstanding basis, presented under the following redemption scenarios:

The following table illustrates varying ownership levels in the Post-Closing Company immediately following the consummation of the business combination in the below redemption scenarios, but, in each case, includes the dilutive effect of the issuance of all Earnout Shares, the issuance of all shares of Post-Closing Company Class A common stock upon exercise of outstanding PlusAI options assumed by the Post-Closing Company, the issuance of all shares of Post-Closing Class A common stock upon the release of unvested PlusAI RSUs assumed by the Post-Closing Company, and the issuance of all shares of Post-Closing Company Class A common stock initially reserved for issuance under the Incentive Plan and the ESPP:

See the sections entitled “Proposal No. 1 — The Business Combination Proposal — General — Impact of the Business Combination on Our Public Float” and “Unaudited Pro Forma Condensed Combined Financial Information” for more information.

The estimated net cash per share of CCIX shares that is being contributed by CCIX to the Post-Closing Company is calculated as the quotient of (1) (a) the amount of funds held in the trust account (under each of the scenarios presented above), less (b) the amount of estimated CCIX transaction expenses of $25.0 million, divided by (2) the number of CCIX Class A Ordinary Shares anticipated to be outstanding as of immediately prior to the Closing (assumed to be 36,662,500 shares under the No Redemption Scenario, 29,475,000 under the 25% Redemption Scenario, 22,287,500 under the 50% Redemption Scenario, and 10,650,587 shares under the Maximum Redemption Scenario). The estimated net cash per share of CCIX shares that is being contributed to the Post-Closing Company (under each of the scenarios presented above) is less than the $10.00 per share ascribed to such shares in the Merger Agreement or the amount per share that holders of CCIX’s public shares would be entitled to receive upon exercise of their redemption rights (which, for illustrative purposes, was approximately $10.48 per share as of June 30, 2025, the CCIX record date).

Under CCIX’s current articles of association, CCIX's directors have the authority to resolve that CCIX be registered by way of continuation in a jurisdiction outside the Cayman Islands or such other jurisdiction in which it is for the time being incorporated, registered or existing (including, but not limited to, the approval of the organisational documents to be adopted by the Company in such other jurisdiction to the extent applicable). Accordingly, it is not necessary for CCIX to receive shareholder consent to the Domestication, and the Domestication Proposal and the Organizational Documents Proposal are therefore being presented to CCIX shareholders on a non-binding advisory basis only.

To effect the Domestication, CCIX will file an application to deregister with the Cayman Islands Registrar of Companies, together with the necessary accompanying documents and fees, and file the Proposed Certificate of Incorporation and a certificate of corporate domestication with the Secretary of State of the State of Delaware, under which CCIX will be domesticated and continue as a Delaware corporation.

The approval of the domestication proposal is a condition to closing the business combination under the Merger Agreement. The approval of the domestication proposal requires a special resolution, being the affirmative vote of holders of at least two-thirds of the CCIX Ordinary Shares represented at the extraordinary general meeting by attendance via the virtual meeting website, in person or by proxy and entitled to vote at the extraordinary general meeting, voting together as a single class. Abstentions and broker non-votes, while considered present for the purposes of establishing a quorum, will not count as votes cast at the extraordinary general meeting.

CCIX does not expect to have significant cumulative earnings and profits, if any, on the date of the Domestication. However, the determination of earnings and profits is complex and may be impacted by numerous factors (including matters discussed in this proxy statement/prospectus). It is possible that the amount of CCIX’s cumulative net earnings and profits could be positive through the date of the Domestication.

As discussed more fully under “Proposal No. 1 — The Business Combination Proposal — Material U.S. Federal Income Tax Consequences of the Business Combination to CCIX Shareholders — Tax Effects of the Domestication to U.S. Holders — 5. PFIC Considerations,” CCIX believes that it is likely classified as a PFIC for U.S. federal income tax purposes. If CCIX were classified as a PFIC for U.S. federal income tax purposes, then notwithstanding the U.S. federal income tax consequences of the Domestication discussed in the foregoing, proposed Treasury Regulations under Section 1291(f) of the Code and certain other PFIC rules (which have retroactive proposed effective dates), if finalized in their current form, generally would require a U.S. Holder to recognize gain on the exchange of CCIX Class A Ordinary Shares for CCIX Class A Common Stock or CCIX Warrants for CCIX Delaware Warrants pursuant to the Domestication. Any such gain would be taxable income with no corresponding receipt of cash in the Domestication. The tax on any such gain would be imposed at the rate applicable to ordinary income and an interest charge would apply based on a complex set of rules. The proposed Treasury Regulations provide coordinating rules with other sections of the Code, including Section 367(b), which affect the manner in which the rules under such other sections apply to transfers of PFIC stock. However, it is difficult to predict whether, in what form, and with what effective date, final Treasury Regulations under Section 1291(f) of the Code and such other PFIC rules may be adopted and how any such Treasury Regulations would apply. Importantly, however, U.S. Holders that make or have made certain elections discussed further under “Proposal No. 1 — The Business Combination Proposal — Material U.S. Federal Income Tax Consequences of the Business Combination to CCIX Shareholders — Tax Effects of the Domestication to U.S. Holders — 5. PFIC Considerations” with respect to their CCIX Class A Ordinary Shares are generally not subject to the same gain recognition rules under the currently proposed Treasury Regulations under Section 1291(f) of the Code. Under current law, no such elections may be made with respect to CCIX Warrants. For a more complete discussion of the potential application of the PFIC rules to U.S. Holders as a result of the Domestication, see “Proposal No. 1 — The Business Combination Proposal — Material U.S. Federal Income Tax Consequences of the Business Combination to CCIX Shareholders — Tax Effects of the Domestication to U.S. Holders — 5. PFIC Considerations.”

Each U.S. Holder is urged to consult its own tax advisor concerning the application of the PFIC rules, including the proposed Treasury Regulations, to the exchange of CCIX Class A Ordinary Shares for CCIX Class A Common Stock and CCIX Warrants for CCIX Delaware Warrants pursuant to the Domestication.

Moreover, U.S. Holders of CCIX public shares exercising redemption rights will be subject to the potential tax consequences of the Domestication.

Additionally, the Domestication may cause Non-U.S. Holders (as defined in “Proposal No. 1 — The Business Combination Proposal — Material U.S. Federal Income Tax Consequences of the Business Combination to CCIX Shareholders”) to become subject to U.S. federal withholding taxes on any amounts treated as dividends paid in respect of such Non-U.S. Holder’s PlusAI common stock after the Domestication.

The tax consequences of the Domestication are complex and will depend on a holder’s particular circumstances. All holders of CCIX Class A Ordinary Shares or CCIX Warrants are urged to consult their tax advisor regarding the tax consequences to them of the Domestication, including the applicability and effect of U.S. federal, state, local and non-U.S. tax laws. For a more complete discussion of the U.S. federal income tax considerations of the Domestication, see “Proposal No. 1 — The Business Combination Proposal — Material U.S. Federal Income Tax Consequences of the Business Combination to CCIX Shareholders.”

Additionally, the Merger Agreement provides that the consummation of the business combination is conditioned upon CCIX having at least $5,000,001 of net tangible assets as of the Closing. There are no other closing conditions based on the amount of the Available Closing SPAC Cash or otherwise based on the amount remaining in the CCIX trust account following the exercise by CCIX public shareholders of their redemption rights.

For a summary of the conditions that must be satisfied or waived prior to completion of the business combination, please see the section entitled “Proposal No. 1 — The Business Combination Proposal — Certain Agreements Related to the Business Combination — Merger Agreement — Conditions to Closing General Conditions.”

CCIX’s current articles of association permit the chair of the extraordinary general meeting to adjourn the extraordinary general meeting from time to time and from place to place either (1) with the consent of any general meeting at which a quorum is present (and shall if so directed by the meeting); or (2) without the consent of such meeting if, in his or her sole opinion, he or she considers it necessary to do so to: (a) secure the orderly conduct or proceedings of the meeting; or (b) give all persons present in person or by proxy and having the right to speak and / or vote at such meeting, the ability to do so. No business shall be transacted at any adjourned meeting other than the business left unfinished at the meeting from which the adjournment took place. When a meeting, or adjourned meeting, is adjourned for 14 days or more, notice of the adjourned meeting shall be given in the manner provided for the original meeting. Save as aforesaid, it shall not be necessary to give any notice of an adjournment or of the business to be transacted at an adjourned meeting.

The approval of the domestication proposal and the organizational document proposal require approval by special resolution, being the affirmative vote of holders of at least two-thirds of the CCIX Ordinary Shares represented at the extraordinary general meeting by attendance via the virtual meeting website, in person or by proxy and entitled to vote at the extraordinary general meeting, voting together as a single class. Accordingly, if a valid quorum is established, a CCIX shareholder’s failure to vote by proxy or to vote at the extraordinary general meeting with regard to the domestication proposal and the organizational documents proposal will have no effect on such proposal. Under CCIX’s current articles of association, CCIX's directors have the authority to resolve that CCIX be registered by way of continuation in a jurisdiction outside the Cayman Islands or such other jurisdiction in which it is for the time being incorporated, registered or existing (including, but not limited to, the approval of the organisational documents to be adopted by the Company in such other jurisdiction to the extent applicable). Accordingly, it is not necessary for CCIX to receive shareholder consent to the Domestication, and the Domestication Proposal and the Organizational Documents Proposal are therefore being presented to CCIX shareholders on a non-binding advisory basis only.

Notwithstanding the foregoing, a holder of CCIX public shares, together with any affiliate of such holder or any other person with whom such holder is acting in concert or as a “group” (as defined in Section 13(d)(3) of the Exchange Act), will be restricted from seeking redemption with respect to more than 15% of the CCIX public shares. Accordingly, all CCIX public shares in excess of 15% held by a CCIX public shareholder, together with any affiliate of such holder or any other person with whom such holder is acting in concert or as a “group,” will not be redeemed without the prior written consent of our directors.

Under the Exchange Act, the business combination may be consummated only if CCIX has at least $5,000,001 of net tangible assets after giving effect to all holders of CCIX public shares that properly demand redemption of their shares for cash on the date that is two business days prior to the date of the extraordinary general meeting.

Pursuant to the Sponsor Agreement, the Sponsor and the Insiders have agreed to waive their redemption rights with respect to all of their CCIX Ordinary Shares in connection with the consummation of the business combination and, because of this, such CCIX Ordinary Shares are excluded from the pro rata calculation used to determine the per share redemption price. As is customary in transactions of this type, the Sponsor and the Insiders did not receive any consideration for waiving their redemption rights.

Any request for redemption, once made by a holder of CCIX public shares, may be withdrawn at any time up to the time the vote is taken with respect to the business combination proposal at the extraordinary general meeting. If you deliver your CCIX public shares for redemption to CCIX’s transfer agent and later decide prior to the extraordinary general meeting not to elect redemption, you may request that CCIX’s transfer agent return the shares (physically or electronically). You may make such request by contacting CCIX’s transfer agent at the address listed at the end of this section.

Any corrected or changed proxy card or written demand of redemption rights must be received by CCIX’s transfer agent at least two business days prior to the initially scheduled vote taken on the business combination proposal at the extraordinary general meeting or such later date as our board of directors may determine. No demand for redemption will be honored unless the holder’s stock has been delivered (either physically or electronically) to the transfer agent at least two business days prior to the initially scheduled vote at the extraordinary general meeting.

If a redemption demand is properly made as described above, then, if the business combination is consummated, CCIX will redeem such CCIX public shares for a pro rata portion of funds held in the trust account. If you exercise your redemption rights, then you will be exchanging your CCIX public shares for cash.

All shareholders considering exercising redemption rights are urged to consult their tax advisors on the tax consequences to them of an exercise of redemption rights, including the applicability and effect of U.S. federal, state, local and non-U.S. tax laws.

If you are a holder of record of CCIX Ordinary Shares on the CCIX record date, you may vote at the extraordinary general meeting via the virtual meeting website or by submitting a proxy for the extraordinary general meeting. If you attend and vote at the extraordinary general meeting, you will automatically revoke any previously submitted proxy. You may submit your proxy by completing, signing, dating and returning the enclosed proxy card in the accompanying pre-addressed postage paid envelope no later than the time of the extraordinary general meeting or, if the meeting is adjourned, the time for holding such adjourned meeting. If you hold your CCIX Ordinary Shares in “street name,” which means your shares are held of record by a broker, bank or nominee, you should contact your broker to ensure that votes related to the shares you beneficially own are properly counted.

In this regard, you must provide the broker, bank or nominee with instructions on how to vote your CCIX Ordinary Shares or, if you wish to attend the meeting and vote, obtain a proxy card from your broker, bank or nominee.

Churchill Capital Corp IX

640 Fifth Avenue, 14th Floor

New York, NY 10019

Attention: Jay Taragin, Chief Financial Officer

Email: info@churchillcapitalcorp.com

or:

Morrow Sodali LLC

333 Ludlow Street, 5th Floor, South Tower

Stamford, CT 06902

Call Toll-Free: (800) 662-5200 or (203) 658-9400

Email: ALCC.info@investor.morrowsodali.com

To obtain timely delivery, our shareholders must request any additional materials no later than five business days prior to the extraordinary general meeting. You may also obtain additional information about CCIX from documents filed with the SEC by following the instructions in the section entitled “Where You Can Find More Information.” If you are an eligible holder of CCIX public shares and you intend to seek redemption of your shares, you will need to deliver your stock (either physically or electronically) to CCIX’s transfer agent at the address below prior to the vote at the extraordinary general meeting. See the section entitled “Extraordinary General Meeting of CCIX Shareholders — Redemption Rights.”

If you have questions regarding the certification of your position or delivery of your shares, please contact:

Continental Stock Transfer & Trust Company

One State Street Plaza, 30th Floor

New York, NY 10004

Attn: SPAC Redemption Team

Email: spacredemptions@continentalstock.com