Why don't you raise full pot?

Anyway i don't think you should leave here. You admit that he might have a hand as bad as bare gs otf, so he might have any other draw or single pair ott for sure. It's unfortunate that you are holding extra spade and two aces that are blocking some of his possible draw hands, but still there are many worse hands in his range he's getting in with.

Have to pot/gii here. If he has 9T it sucks but there's 5 different cards that bring straight draws with a 10 or A being the most likely as he's definitely calling all Q10s but not all 109s. In terms of him calling with 2 pair, we're a 35% dog if this happens and we need 38% to b/e here. We expect him to shove KJ otf so we're worried about K7 and J7 which is only a tiny amount of his range whens he's this loose. We block an 8 which makes it less likely he has paired the turn.
Just an FYI, if you'd of potted the flop to $15 you'd need 35% to b/e ott so you wouldn't even be worried about 2 pair. 

I agree with you guys that check-potting against a villain this unaware and on a board this wet would have been a better play. In general I'm a little wary of making check-potting the flop my standard. There are a lot of players in my games whose flop strategy is check-pot their nutted hands, check-call marginal, and check-fold everything else, and I think this is an incredibly easy strategy to defeat. But that doesn't have much relevance to this hand, potting would have been better.

That turn does truly suck but vs this villain I'd shove here. Offmenut is correct when he says we need close to 38% (if we assume he NEVER folds) and we have 39,5% vs (KK,JJ,77,88),((KJ,K7,K8,J7,J8,78)!(KK,JJ,77,88)),ss,T9.

Now that I think about it, the 8d isn't even THAT bad of a turn. I mean, it's ugly, but so is nearly every card that doesn't bring in our flush. It's a lot better than the Td for example. I think our best plan on the flop is probably to check-pot and jam every turn, knowing that a lot of them will look pretty bad.

Don't have much to add other than that the 8 is a little interesting because I think that we loose some fold equity that we could have had.  Villain will improve on this card often but some of those hands are draws that we are ahead of, some are made hands that we have good equity against and other times we are drawing to the flush.  Either way I would just pot/gii with our equity given the range that villain can be on.