Facing a flop push

I had just sat down at a 1/2 6max NL table. I had ~$300 from winning a nice pot some hands before this one:

I have 9c8c UTG and double the BB and everyone calls.
the flop comes Jc9d5c and it's checked to me and i bet half the pot. The guy after me pushes with ~$220..
I don't really know anything about his play as I just sat down.

So what do you think, call or fold? what hands can he possibly have that you push this flop with? 55? Ax clubs?

And what do you think about my flop play? preflop is just to mix it up.

thx bye