Live Stud8 Game. Folds to me in last position with (A2) A and I complete. The bring-in (XX) 5 calls

The bring in player is older and on the passive side. Misses value in some key spots but otherwise plays good. Is a decent winner in this lineup.
I think he never 2-bets me here and his range is 3 low, wired pairs 8 and lower, he might possibly fold 99-JJ, might not but def playing QQ/KK. He has all split 5's with a low kicker and most likley with a high kicker as well, though there is a very small chance he folds some of those to the bring in. He also has all 3 flushes but I dont remember the suits on this hand except that the boards were mostly rainbow

4th Street:
(A2) AK Check : Call
(XX) 57 Bet

I will check/call with my range here.

5th Street:
(A2) AK9
(XX) 579
'
On this street Im not sure what to do. Its very unnatural to lead this card after check/calling fourth. Also because my opponent semi-bricked I dont expect him to nessecarily keep betting, although he might. I think he leans towards checking because of his passiveness.

This is the question I have of whether I check/call, check/raise, or lead here? I think if I check and he bets I will check raise but I dont know whether its better to just lead this 5th street even though its awkward. How bad is it if it goes check/check?

Follow up questions from my opponents perspective:
1) If he has 4 low here on 5th against my board and I check, should he bet?
2) If he has a split/wired pair and 3-low on 5th against my board and I check, should he bet?

Thank you!

Probably raising 100% on 3rd. It should depend on number and size of antes and exposed cards, but vs "never 2-bets me" I think you should be really close to that.

kc range on 4th seems fine. you have very little that's able to 2bet.

I think 5th comes down to pot size. Passive player type should play reasonably well facing bet or check. The issue is that he's got relatively few hands that punish our bet (straight, trips) but many combos that take a free card vs check. As the pot gets bigger, the cost of that free card grows. So large ante 8-handed game is a clear bet and huhu check/mix seems fine. 8 handed 5/5/20/40 I would lean bet. 1/2/4/8 with a large rake I would lean check. As always, exposed cards could sway things (e.g., our two pair outs are deadish; his straight cards are dead)

1) depends on pot size. he should fight more for bigger pots. But having played a lot against this type, it seems like he won't.
2) mostly same as 1 except I think this type bets the pair more frequently than the bare low draw.

I like x/c range on 4 and x/r on 5. He should be betting range here.

I don't know about this. I'm not a passive player, and as villain I would check behind with almost all of my range on 5th. The 9 was likely the worst card in the deck for him. Why would you think he should bet range when he's almost certainly a dog here?

Cause he's not. He at least has 2 low, semi-connected cards and you have AK9. You have to fold here a lot, so he should bet.

He's a favorite against a pair of aces?

I get that he is if hero has nothing, but I wouldn't assume that.

His range is a favorite over our at this point, obv not over AA. We have to x/f a ton here

Huh, well I had forgotten that hero raised first in as last position so he could have started with nothing, but it still seems rare that I would fold in his position, and I don't think someone described as passive is usually going to bet after getting bricked on 5th.

When you x/c 4th, it looks like you have a high hand, so normal to bet 5th when both lows brick.

No because you're x/c'ing your whole continue range on 4

I would just bet 5th, and I don't think it's unnatural. OP said he thinks villain is more likely to check behind.

You are c/fing a good part of your range on 4th street. You could have been on a steal last to act with an ace. You might also fold some weak 3-card lows. A lot of what you continue with is pairs, sometimes something like (44)A or (JJ)A, rather than split aces.

I would never check 4th street and I'm never checking 5th street either.