Local MTT satellite for local tournament series - I would personally call this lowstakes as far as skill level but according to the posting guidelines it's mid-stakes.

about 20 people remaining out of 70 entries, most of the fish are gone but still a couple bad players even at my table.

Hero with around 15bb or so opens 2bb on CO, Ac4c
folds to Villain (no reads) in BB who flats, covers Hero with about ~40bb-ish.

Flop is AsQh7h
Villain checks, Hero bets 1bb, Villain calls
Turn is 9c
Villain checks, Hero bets 1.5bb, Villain calls
River is 5d
Villain checks, Hero checks behind

Thinking I should have sized up turn to 2bb, maybe 2.5bb.
Personally I don't hate checking behind on river to get to showdown with top pair bad kicker when Villain covers me with a way bigger stack, but i could be convinced this is a bet/fold spot for a few bb. Thoughts?

Will post outcome later

Some key details are missing: was there an ante? how many positions get a seat? what was your relative position in the field?

No ante, bottom 50% of stacks but closer to median stack, top 6 win satellite.

Ok, line looks good. Small bet/fold on the river might garner some EV but also opens you up to getting shoved on by bluffs. There isn't much value for villain to x/jam river so you may end up needing to call the jam. Depends on the type of player you are against whether to go for that small bet.

In some dynamics you could size up turn to shove river. Everything bricked so you can have lots of bluffs, and villain can have lots of missed draws and their stronger Ax will shove pre, so they may end up finding a call with worse pairs.

Outcome: villain shows 9h2h and says they wouldn't have called turn if not for the 9

I like a larger bet on the turn and get it in on the river when he checks again. I think with tinybet/tinybet you have a really awkward stack to pot on the river, but you still have to put something out there. You have top pair with shallow stacks, you need to get as much value as you can, especially with a brick river.

I would bet about 2.5 to 3 bb's on this flop (given there is no ante). It crushes our range but not the BB's range. I would then check back the turn. This makes it look like we could be bluffing. I would call a river bet then.

As played I would always fold to a river c/r so I don't mind the check back. Also there are a bunch of Ax hands that beat us.

With 15 bb's I probably open shove pre-flop. But without an ante maybe I wouldn't (haven't been in this type of situation since forever).

Off the top of my head I think you could size up to 1/3 pot on flop and turn. (That would be, in this case, 1.5BB then 2.5BB.)

I generally don't ever bet the flop too large off this stack, but on a board this connected I don't want to give the draws a correct price to continue, either.