If you paly your pocket pair for the set value, if you don't touch your flop it's check fold.. Maybe some times a bet if the flop is low but that's all. Play it like a draw
The second possibility is to be agressive pre-flop, and do continuation bet except on very dangerous flop (AK6/KQJ) but JJ9 is a very good flop for a pocket six if you had raise before the flop