Hand 1:
We're in the bb against 2 100 bb stacks with 10s9s98.

mp raises, co calls, we call. We donk 10h8h3 for close pot. Call, call.
Turn is the 8. I would always bet here hu, but don't mind checking to let the initial raiser bet his overpairs which are likely folding to a bet. I also think it also looks awfully strong leading into 2 people there and I don't mind them catching up with draws.
So I check, mp checks, co bets close over half pot.
We call, river is a 10.

I'm pretty sure I butchered this hand. I think leading turn, ship river is the better play here.

Hand 2:
We raise AA103 off in the sb against bb who is 3 betting. We call being 300 bbs deep.
Check calling Ks64 rb. Turn Js gets checked through. River A.

Ok, now I feel dumb posting this. This should just always be a check/call.
He probably never has 2p+ and we should give him some rope with his air to rep the Ace as the aggressor.

Hand 1:
I really really dislike the donk here. We have a very strong hand especially with the 9 blockers and there are a ton of draws out there. Those draws are likely to bet and depending on the draw a lot of time they will be calling a check-raise. We have the blockers so we make hitting straight pretty dang hard unless a 9 rolls off.

I would go for the check-raise flop.

With the boat pairing giving us the effective nuts, I would probably check the turn oop. It disguises are hand a little and maybe we look like a combo draw, let them rep. I would go for the check-raise again if they bet. I don't think they would double barrel bluff very often after getting called on that board so getting them to bluff on the river is unlikely.

River:
I would shove pretty much everything, if I checked turn and they also checked it back I think we have to check river. Unlikely to get a call and I'll take what little bluff equity I have.

Hand 2:
I would play the hand pretty much the same. I would lead river for 2/3 sizing. I know the ace hits his range harder but we literally have AA and there are a bunch of 2-pairs combos that will call. I don't think he would bluff missed spades because if he had spades we'd have been him fire big on turn. Likely has air which has probably given up or weak showdown value that is not likely to bet. I want to charge that showdown.

That's not true. Villains play pretty reasonable these days. Betting with draws they can bet/call and checking back with draws they can't stand any heat.

Hand 1: I like donk OTF. I also believe there are draws that will call the donk and will fold to c/r.

I would c/r the turn. Calling the turn and leading the river is such a strong line and I don't think there is much our villain can call you down with. c/r the turn polarises your range a bit and villain is more likely to make a hero play I believe.

Hand 2: I would probably bet the river.

This is overthinking it; two nines are nothing special as sidecards for T8 in this spot.