The show "The Looming Tower" on Hulu documents this well, would recommend checking it out if you want to learn more. It also documents how the CIA and NSA basically froze the FBI out of key intel. What I find super ironic is this freezing is a large reason why the attackers were not stopped earlier, but rather than solve this issue, Cheney and his lawyers gave way more power to the NSA to surveil Americans without encrypting their names or any details, further creating a siloing between the intelligence communities.