Of course Bush didn't know specifics of it beforehand. That is the Bin Laden line, along with "Mossad did it". It is absurd on its face, raving X-files paranoia. That the Dems are jumping on it only shows how desperate they are and that they have no other issue. Such nonsense is a perfect "equal opportunity" for nutjobs, because no relation to facts is necessary at all. It would be utterly trivial to spin out a story line that has congressional Dems nefariously behind it all, but it would also be lying and beneath contempt.
Of course Bush didn't know beforehand. He didn't do anything because he didn't, and would have if he had. Because he is not a Martian. Double Duh. The fact that any of it is being brooded about at all is absurd. Yes thousands were murdered and Islamic terrorists did it. Not Mossad, the Oil Companies, a Vast Right-Wing Conspiracy, Cattle Mutilators, or Orbital Mind Control Lasers. Buy a clue.