Bush wanted to finish his daddy's war, because the Saudi government wanted Iraqi oil production disrupted/brought to heel.
Bush was trying to drum up support for military action against Saddam from day one, but in a sort of lazy way. He spent several months of his first year in office on vacation.
Anyway, Bush had been told about Bin Laden, and Bin Laden's people being in the US in early August 2001.
There were other warnings, but all of them were ignored.
Here's another fun fact, Daddy Bush was in a meeting of the Carlyle group on 9/11. Also present, were members of the Saudi royal family, and the Bin Laden family.
Baby Bush personally granted exemptions to the nationwide no-fly zone after 9/11 to let the Bin Laden family members flee to Saudi Arabia.
Also of note, the Carlyle group made a shitload of money in the newest venture, Defense Contracting. Specifically, they owned the production facilities that made the Abrams tank.