EX-99.(a)(9)

ClearBridge Energy Midstream Opportunity Fund Inc.

/s/ Marc A. De Oliveira

/s/ Jane E. Trust

Name: Marc A. De Oliveira

Jane E. Trust

Title: Secretary and Chief Legal Officer

President and Chief Executive Officer

Exhibit (a)(9)

CLEARBRIDGE ENERGY MIDSTREAM OPPORTUNITY FUND INC.

CERTIFICATE OF CORRECTION

THIS IS TO CERTIFY THAT:

FIRST: The title of the document being corrected is Articles Supplementary (the “Articles”).

SECOND: The sole party to the Articles is ClearBridge Energy Midstream Opportunity Fund Inc., a Maryland corporation (the “Corporation”).

THIRD: The Articles were filed with the State Department of Assessments and Taxation of Maryland (the “SDAT”) on October 19, 2026.

FOURTH: The definition of “Original Issue Date” in Section 12 of Article FIRST of the Articles as previously filed with the SDAT is set forth below:

“Original Issue Date” means (i) November 11, 2026 for the Series S MRP Shares and the Series T MRP Shares and (ii) December 9, 2026 for the Series U MRP Shares.

FIFTH: The definition of “Original Issue Date” in Section 12 of Article FIRST of the Articles as corrected hereby is set forth below:

“Original Issue Date” means (i) November 12, 2026 for the Series S MRP Shares and the Series T MRP Shares and (ii) December 9, 2026 for the Series U MRP Shares.

SIXTH: The undersigned acknowledges this Certificate of Correction to be the corporate act of the Corporation and, as to all matters or facts required to be verified under oath, the undersigned acknowledges that, to the best of such officer’s knowledge, information and belief, these matters and facts are true in all material respects and that this statement is made under the penalties for perjury.