I think the World Trade Center attack had more to do with eight years of Clinton than eight months of Bush.
I think it is understandable that Donald Trump, after losing hundreds of friends when the World Trade center came down, thinks that George W. Bush did not keep us safe.
I think this comes from the heart, and not from some idea that he will say anything to get elected.
Especially since the Clinton people, possibly on purpose, left the WH in a dismal mess. It took quite an effort and quite awhile to merely get it back into proper functioning order.
The whole thing took a long time to carry out. Longer than the time Bush was in office. The only possible thing Bush could have had to do with it if it were an inside inspired operation (not likely that it was) was to have given it his nod. It would have to have been on Clintons watch that most of it was planned and put into practice.
As an interesting side note is even the picture of Satan in the smoke of the TC looked amazingly like a cross between Clinton and Satan.
Any way you slice it Trump is on the wrong track.