That's getting into conspiracy theory territory. I guess you don't like being a member of this board very much.
The 9/11 plot was already in development even before the election, even before people knew that it was going to be a Bush vs. Gore campaign.
Two options come to mind. One is that Gore appoints someone different as Attorney General and Secretary of Defense, and a few other lower positions, that works out better than OTL and they learn of the plot or of a plot in general before 9/11, disrupting the operation.
That or if it happens as in OTL, Gore may or may not develop some sort of Homeland Security department, but more than likely I see no Iraq and him pouring a lot more manpower into Afghanistan from the beginning. Not gradually building up over several years.