I really, really hate when people hijack 9/11 for political reasons because the first thing that goes out the window is the truth.
There were failures of BOTH the Clinton and Bush administrations that led to 9/11, period. What Bush did or didn't do AFTER 9/11 he totally owns. Did do: tragically decided to invade and occupy both Afghanistan AND Iraq, which had zero to do with 9/11. Didn't do: ever catch bin Laden. Even let him get away when we had him in Tora Bora, as has been pointed out above. As also pointed out above, he pretty much diverted all attention to Iraq when he decided the man who needed to be caught and killed was Saddam Hussein.
We had to wait for Obama to get OBL. Any suggestion that this somehow was George W. Bush's doing is the worst kind of ignorance and ass-clownery.