You under-rate the Saudi intelligence services.
Whatever we may think of them, if anything, the Saudi gov is not stupid. They had nothing to gain, only lose by supporting or condoning a terrorist attack on the US.
Just because Bin Laden was born there, doesn’t mean the Saudi government had anything to do with the attack on the US on 9-11.
As I recall from previous articles some time ago — Bin Laden and his terrorists wanted to kill the political leaders of Saudi Arabia also.