Osama comes from a construction family so right off the bat he knows how to engineer an attack on buildings, bridges, dams etc because he knows how they are put into place.
Yes, the CIA worked with Saddam, Noriega, Bin Laden, etc. As Rabbi Kahane said, "Nations have no permanent friends, just permanent intersts." We've all had people we used to be friends with and now can't stand. Osama has engineered attacks on his fellow Saudis so there is certainly a rift there. Osama had a falling out with America when we replaced his mujaheddin fighters to fight Saddam and landed in Saudi Arabia. Americans, according to Osama, defiled the Saudi peninsula by stepping foot there. That's when he became an enemy of the US. We couldn't see beyond the Cold War and never thought a bunch of terrorist idiots would be a serious threat to national security like a nuclear armed Soviet Union was.
Every president since FDR has said that oil is critical to our survival and that the Saudis must be worked with to protect our security. Why would they then endanger that security by using Saudi and UAE pilots to conduct the attack?
The Saudis never declared war on the US officially and they know that the way to defeat the West is through immigration, resource purchases and $$$. Also, no administration has the cahonas to bomb Mecca. Unless we get MasterWolf or somebody like that in the White House, it's not going to happen. American leaders are too chicken and too ignorant to make that decision. The Saudis say they're America's Friend and the Americans have never heard of takia.