trouble with middle pairs (77)

[Yerma]

For what it's worth, I think you played this well. You're quite often looking at a 9 having called you. But sometimes it's just A-high or a deuce or smaller pocket pair. You'll catch most of those weaker holdings if you bet, but you won't induce a bluff from them very often. Also, you won't get raised by the 9 very often so you're not risking very much by betting the river.

I would probably raise preflop though. But it's no big deal.

[Niediam]

Raise preflop. Don't donk the turn.