People will flop two-pair when you have an over-pair. It happens. Personally I prefer getting sucked out on real early though.

If it's any comfort to you - the exact same thing happened to me at a FFP sat to the Scandinacian open yesterday - only it was the third hand of the tournament - and I had kings against J9.

You played fine. I don't see how you could justify not pushing here - given there was no re-raise pf. You would have to be Uri Geller to put him on two-pair.