I'd fold preflop, I don't think you'll be making enough money in this spot unless you know villain is a big fish.

Postflop basically all options suck. Checking down will be +EV and I think you'll have minimal fold equity on the turn. Ax doesn't fold, neither does Kx, most Qx will have either another pair or some sort of draw, same for Jx Tx. 9x 8x of course have pairs but will still probably call one bet. So betting turn sucks unless you want to go bet bet and I think that's too optimistic against an unknown. I'd check down.

I used to defend all these small pocket pairs in the small blind no matter where the open raise came from, but versus early position raise and no callers I don't bother anymore unless the opener is a poor player. The problem is exactly as you see it here, even if we hit our set it's not going to be easy to get paid off.
Being out of position makes it hard to get the money int he middle and we need that to make our pair pay., usually difficult enough, but especially so if our opponent plays as passive as this one.

As played it's a wet board and not a lot we can do, we don't need to start bluffing I think we may on occasion have the best hand. I play as suggested my komododragonjesus and check it down.

Yeah unless villain is a recreational player I wouldn't defend this given the lack of position and obvious range advantage of the villain. Given that range advantage I also wouldn't fight on most of the board textures especially those containing Aces and Kings that should hit villain's range fairly well.