No its surely not a bluff. Betting into the preflop raiser on that flop is suicide unless you have some of it.

Whether he has u beat or not is another question which is dependent on any reads u have.

I think he is asking the same question you are asking. "Do you have an Ace ?".

Call is a better option as u will only have your push called by a hand like Ax or TT.

If he checks the turn then your push/bet should take the pot down