First, profanity is not necessary.
I don't know the answer as to why planes were scrambled faster in the Payne Stewart incident. I do know that the USAF planes were already in the air over the Southeastern U.S. since their home base was Eglin. They were re-routed to do a visual inspection of the non-responsive plane. Perhaps fighter planes were less common in the skies over NY and Boston.
AND it's entirely different dealing with one wayward plane vs. the chaos that prevailed on the morning of 9/11. You see nefarious. I feel total sympathy for the controllers, airline employees, military personnel and politicians who were desperately trying to make sense of the torrent of information flowing toward them that tragic morning.