3/6 NL is he being tricky/whats my line?

[tdarko]

i have sat with villain plenty of times, i have seen him limp reraise with AA plenty of times(though its not AA 100% of the time). he's a tricky player.

villain: $670
hero: $640

villain is UTG and limps i am in the CO with 99 and raise it to $30 (probably bad since he limped UTG and should have sent of warning bells), villain reraises to $100, hero calls.

flop (K [img]/images/graemlins/heart.gif[/img]8 [img]/images/graemlins/diamond.gif[/img]3 [img]/images/graemlins/club.gif[/img])~209
villain checks???, hero checks.

turn(K [img]/images/graemlins/heart.gif[/img]8 [img]/images/graemlins/diamond.gif[/img]3 [img]/images/graemlins/club.gif[/img]9 [img]/images/graemlins/heart.gif[/img])~209
villain bets $200, hero???

did he check a set of kings here, this was a very friendly flop for a set of kings and IMO not a terrible move to let me catch a piece of my hand with no draws on the board. i just have never seen him do this with kings is all.

any thoughts?