Why are you betting the flop? If the turn was a Q/K/T are you betting again (I'm wondering if you planned on turning 99 into a bluff by betting the flop), because if I bet the flop that would be my plan.

As it's 5nl, I would most likely just check back than go on a 3 barrel bluff.

I don't think it's a horrible flop bet. We at least give ourselves that protection element, and maybe even fold out stuff like TT.

As played, we should just give up after flop bet is called. Checking flop is just about reasonable with this holding also, although as our pair gets weaker, the protection element gets more important. So we should probably bet the flop with some weaker PPs.

I don't mind the flop bet but might make it even smaller.It's only to avoid giving a free card if he has something like KQ. If I had a hand like KJs which isn't vunerable but still has second pair I would definitely check back.

As played I'm only going to fire one then give up as you did.