There was a major, formal investigation of the January 6, 2021 attack on the U.S. Capitol, comparable in seriousness and scope to the 9/11 Commission or the Ukraine (Trump–Ukraine) impeachment inquiry.

Key points:

• On June 30, 2021, the U.S. House of Representatives established the Select Committee to Investigate the January 6th Attack on the United States Capitol via H.Res. 503. This was a high‑profile, official congressional investigative body with subpoena power, public hearings, and a broad mandate to investigate the causes and events of January 6 and make legislative recommendations, much like prior major congressional inquiries.
• The Committee conducted extensive hearings (including widely watched televised sessions in 2022), interviewed hundreds of witnesses, collected voluminous records, and issued a lengthy final report with findings and recommendations—mirroring the scope and style of the 9/11 Commission and the Ukraine impeachment inquiry processes, even though its institutional form (a House select committee rather than an independent commission) differed slightly from the 9/11 body.
• In parallel, the Department of Justice and other federal law‑enforcement agencies pursued one of the largest criminal investigations in U.S. history related to January 6, further underscoring that the events were indeed “all going to get investigated” in a major, formal way.

Because Jason’s prediction was about the existence and scale of a major official investigation—rather than the exact legal form (independent commission vs. select committee)—and such an investigation clearly occurred, the prediction is best classified as right.