15$ 9men turbo early game post-flop with 88

I am fine with opening 88 there this deep. If you ain't feeling too comfortable with your postflop- just open fold it and play 99+

I like the double barrel on the turn. We get value from draws, maybe we make him fold Ax, KQs or whatever and we very often get to a free showdown on the river, which is also a plus!

I agree with kurrkabin. If we had more information on our opponent (for example if we knew that he likes to call bets on the flop and bet the turn with a wide range when checked to) then we could take a different line sometimes, for example checking the turn to get more value from his bluffs.

Since he is unknown we just go ahead and bet the turn and again we pretty much always have to fold to a raise since it signifies a loss of strength.

Incidentally, if the board had been QJ7, we might consider check/folding on the flop already and certainly not double barrelling.