He isn't folding JJ-99. Your general purpose floating a board like this in a 3bet pot is getting villain of his non-pair cards. In your case getting AK-AJ to fold.
you think 99 continues here? that is pretty marginal since i play AQ the same as how I played this. If i am only getting AJ/AK to fold then this is doubtfully +EV since I put like 25 bb in before firing the turn bullet...