For anyone who doesn't consider themselves a conspiracy theorist, but who still wonders how the hell 9/11 could've possibly happened, I'd highly recommend the 2011 podcast episode "Who Is Rich Blee?" [1] and the documentary "9/11: Press for Truth" [2], both by Ray Nowosielski and John Duffy. They're both critical (as in thinking) without being unhinged -- no inside job shit, no controlled demolition stuff, no "plane was fake". Just a close look at the years and months leading up to 9/11, with some terrific interviews with major players (Richard Clarke, Bush's Counter-Terrorism "Czar"; Mark Rossini, the FBI agent assigned to the CIA's Bin Laden Issue Station who was prevented by the CIA from notifying the FBI that 2 of the 9/11 hijackers had multiple entry visas to the US and were planning to travel there).
The documentary's particularly interesting, as it follows the efforts of four New Jersey women who lost their husbands in the World Trade Center as they struggle to figure out what happened that day. I hadn't realized that a "9/11 Commission" hadn't been planned or even wanted by people in Washington, and that the victims' families had to make a stink to get one created.
[1] https://www.doubleasteriskmedia.com/rich-blee-podcast [2] https://www.youtube.com/watch?v=9KhQXKJCJ5Q