These types of covert operations are compartmentalised. Cheney would have only had need to know information, but they knew.
There are so many insane inconsistencies in all the stories surrounding that day. It is the greatest psy op the US ever perpetrated. I don’t think the attacks were US coordinated. People with influence were able to make sure there where NORAD exercises that day, and ensure plenty of chaos and disorganisation. Cheney would have been able with Rumsfeld to make sure the sector where the object impacted the pentagon was reinforced. The gang who knew what was going on got pretty big, to the point people got put options on the airlines the day before.
But the US really kicked into gear right after it happened. The WTC steel was immediately shipped off to china, there was no investigation about building 7 doing random free fall stuff. And then there was that word: conspiracy theorists. I’m fairly certain a bunch of the ‘theories’ were added by the CIA to make sure people just got fatigue or kept arguing among each other (the same way Trump floods the zone and we all gave up on the Epstein Files).
But I saw what I saw. An Empire in decline with no real enemy and no active war fronts and the biggest war machine as proportion of its GDP. What’s 3,000 people and a whole bunch of inconvenient documents disappearing as price to pay to feed that beast?
Of course Cheney didn’t know, he didn’t have to know.