"In what public venue on the 12th did he term it a terrorist attack..?"
He- and Crowley- both strongly implied at the 2nd debate that his 9/12 Rose Garden "acts of terror" words were specifically addressing Benghazi, and that they weren't (as many believed from the context of the speech) just throw-away, generalized lines the day after the 9/11 anniversary. And in the days following the debate, Obama ran around acting like he meant it was terrorism from the beginning.
Go to run to the store....be back later.