Keith is better than I am, but I'm not so quick to check/fold this flop when I do raise and get called by the button. This flop hits our range more than villain's, and we only have jack high. This is a clear cbet for me, we definitely want villain to have the option to fold. If we're checking this flop, we definitely should not be opening J9s. We should only raise this pre if we get called wide enough for us to profitably bluff Axx and Kxx flops. But we also don't want villain to be calling bottom pair on Kxx when he calls our raises. Given that he did make the flop call, we should not be opening J9s against him in future, except maybe on the button. Pay attention to how loose people are calling, not just this guy but the table in general. J9s is a fine open against a loose-passive table that call too much pre flop and fold easily post flop. These tables definitely exist at 2nl, but it only takes one guy to make bad calls to change the table dynamic.

don't be obsessed with bluffing at 2nl
Agreed. cbetting Axx and Kxx flops with air is generally an ok bluff against loose players, but stop bluffing if you get called or raised. Also, semibluffing big draws like NFD and open enders to the nuts will be profitable at these stakes, partly because we get folds sometimes from better hands, but more because it builds a large pot and makes it harder for fish to get away when we hit the nuts.

But generally, most bluffs will just get you into trouble. People don't fold enough at these stakes. Focus on value, limit your bluffs to situations where the flop hits our range better than villain's (like this one), or we have plenty of nut equity (30%+).

2nl is about taking stacks with your monsters decent pots with medium hands and losing the least with weak hands, Playing shit hands,out of position won't accomplish any of those.
So much this.The only things I will add to this is that J9s flops reasonably well, it's a mediocre hand for me, rather than a shit hand. J9o is a shit hand.