Churchill Capital Corp IX-A美国股票招股说明书(2026-01-27版)

PROXY STATEMENT FOR EXTRAORDINARY GENERAL MEETING IN LIEU OF AN ANNUAL MEETING OF Churchill Capital Corp IX PROSPECTUS FOR UP TO 201,517,063 SHARES OF CLASS A COMMON STOCK OF CHURCHILL CAPITAL CORP IX(TO BE RENAMED “PLUSAI HOLDINGS, INC.” FOLLOWING DOMESTICATION This Proxy Statement/Prospectus Supplement No.1 (this “Supplement”) supplements the proxy statement/prospectus dated January12, 2026 that wasmailed by Churchill Capital Corp IX, a Cayman Islands exempted company (“CCIX”), to its shareholders on or about January12, 2026 (the “ProxyStatement/Prospectus”), in connection with the proposed business combination among CCIX, AL Merger Sub I, Inc., a Delaware corporation and direct,wholly owned Subsidiary of CCIX, AL Merger Sub II, LLC, a Delaware limited liability company and a direct, wholly owned Subsidiary of CCIX, andPlus Automation, Inc., a Delaware corporation (“PlusAI”). CCIX and PlusAI jointly filed the Proxy Statement/Prospectus with the U.S. Securities and The purpose of this Supplement is to update and supplement the information contained in the Proxy Statement/Prospectus with information contained inthe Current Report on Form 8-K (the “Current Report”) filed by CCIX with the SEC on January27, 2026. The Current Report is attached to, and forms This Supplement modifies and supersedes, in part, the information in the Proxy Statement/Prospectus and is not complete without, and may not bedelivered or utilized except in combination with, the Proxy Statement/Prospectus, including any amendments or supplements thereto. Any informationin the Proxy Statement/Prospectus that is modified or superseded by the information in the Current Report shall not be deemed to constitute a part of theProxy Statement/Prospectus except as modified or superseded by this Supplement. This Supplement should be read in conjunction with the Proxy YOU SHOULD CAREFULLY CONSIDER THE MATTERS DISCUSSED UNDER “RISK FACTORS” IN THEPROXY STATEMENT/PROSPECTUS. NEITHER THE SEC NOR ANY STATE SECURITIES REGULATORY AGENCY HAS APPROVED OR DISAPPROVED THE TRANSACTIONSDESCRIBED IN THE PROXY STATEMENT/PROSPECTUS OR THIS SUPPLEMENT, PASSED UPON THE MERITS OR FAIRNESS OF THEBUSINESS COMBINATION OR RELATED TRANSACTIONS OR PASSED UPON THE ADEQUACY OR ACCURACY OF THE DISCLOSURE UNITED STATESSECURITIES AND EXCHANGE COMMISSION FORM 8-K CURRENT REPORTPURSUANT TO SECTION 13 OR 15(d) Date of Report (Date of earliest event reported): January 27, 2026 CHURCHILL CAPITAL CORP IX (Exact name of registrant as specified in its charter) 86-1885237(IRS EmployerIdentification No.) 001-42041(CommissionFile Number) ☒Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)☒Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with anynew or revised financial accounting standards provided pursuant to Section13(a) of the Exchange Act.☐ Item 7.01Regulation FD Disclosure. On January27, 2026, Churchill Capital Corp IX, a Cayman Islands exempted company (“Churchill”), and Plus Automation, Inc, a Delawarecorporation (“PlusAI”), issued a joint press release announcing the postponement of Churchill’s extraordinary general meeting of shareholders to voteupon the proposed business combination between Churchill and PlusAI from February3, 2026 to February11, 2026. The press release is furnished as The foregoing (including Exhibit 99.1) is being furnished pursuant to Item 7.01 and will not be deemed to be filed for purposes of Section18 ofthe Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise be subject to the liabilities of that section, nor will it be deemed to Item 8.01.Other Events. Postponement of Extraordinary General Meeting The extraordinary general meeting of Churchill’s shareholders to approve the proposed business combination between Churchill and PlusAI hasbeen rescheduled from February3, 2026 to February11, 2026. The Board of Directors of Churchill decided to postpone the meeting in order to allowadditional time for Churchill to engage with its shareholders, including following the announcement by PlusAI regarding its expanded partnership withTRATON Group, filed by Churchill on a Current Report on Form 8-K on January26, 2026. The rescheduled meeting will be held on February11, 2026, As a result of the postponement, the deadline for delivery of redemption requests from Churchill’s public shareholders in connection with theproposed business combination has been extended from January30, 2026 (two business days before the originally scheduled extraordinary generalmeeting) to 5:00 p.m. Eastern time on February9, 2026, the second business day preceding the rescheduled extraordinary general meeting. Public All of Churchill’s shareholders of record as of the close of business on January7, 2026, are entitled to vote at the p