The CIA and Saudi Intelligence worked with Al Qaeda all the way up until 9/11, specifically in areas like the Balkans

I think they were trying to recruit these guys to be double agents. They were likely unaware of the 9/11 plans because had they been they would have known there was no way they were going to turn people who’s conviction was leading them to sacrifice their own lives.

I don’t think the CIA or FBI actively helped them plan 9/11, but I do think they were willing to turn a blind eye to an event that would give them both more power