Given I disagree with your premise that the cost of GWB's Iraq war was not kept off the books, I believe we cannot compare income from tax collections prior to/after 9/11 without also taking into account the outflow via 2 tax cuts and an unfunded prescrip drug bill - programs we clearly could not afford. What diff does it make if the gov't took in a great deal of taxes when at the same time the gov't was spending more than we could afford?
I'll watch for how others view your question.
"If you don't think too good, don't think too much" -Ted Williams