$12.5$ NL HE MTT: 6 max MTT

6max: TOURNEY 1500$ GTD. 12.5$ buyin. 17 left, 7 places paid. I am currently 5th.
5 handed
Players involved
LJ 60bb
SB 41bb
BB(Hero) 54bb

LJ limps(he limps all his marginal hands and raises Monsters)
SB called and I raise it to 5bb from BB with Ks9c
LJ folded and SB called.
POT: 11.5bb
Flop: Td6s8c
SB: checks
BB: I bet 4.6 bb
SB: Calls
POT: 20.7BB
Turn: Td6s8c5h
SB: Check
BB: I check back.
River: Td6s8c5hKc
SB: goes all in 31.6bb
BB: I folded.

Please provide some insights for this hand. The mistakes I made during the hand. Was it a correct fold?
And I don't have much info on the villain, but considering how much I played with him, he was one of the good players on the table.
NO HUD data because the sites I play on don't allow it.

Pre flop: Depends what you mean by LJ limps marginal hands. Is a marginal hand A4 or is a marginal hand like 66 or both? I ask because we are making this raise pre to get folds. If we think they have hands that they will not fold (same goes for SB) then this play is bad imo. If we are anything short of fairly confident we will get two folds then we should just check our option here and see a flop. Too many times with two in front of us we get action which may be okay if its the SB since we have position but I think we are setting ourselves up here a bit by trying to steal. Plus if we believe in ourselves post flop then we can possibly take it then. Without knowing stats or the villains I much prefer to just check behind here.

Flop: This one is weird since it is such a check behind board with all the middle cards which should hit the villains range but we also raised pre and want to rep a big hand. Even with raising pre I think I check this one back. We have a draw so we could bet but checking back for pot control (since this pot is bigger already than what it should be imo) is best. If we checked our option pre then this would be a much easier check back on the flop and we would actually have an easier time since our range would/should be perceived wider. As played, if you are going to bet I like the sizing but know there are so many hands that will call like any 9x, 7x, and most pairs.

Turn: This is a spot where if we would have checked the flop and then was checked to again we could bet and "buy" most likely a check to us on the flop where we could check back or bet for value or a bluff depending on the card. As played since we bet the flop and was called I would think Im behind but I actually like betting here to pot control. I know that makes no sense when you read it but if we bet small here then we control the hand and then can control the pot. If we bet small (which would be my play after you raised pre and bet flop) and get raised then its an easy pitch. If we get led into on the river then depending on the river card it should raise some eyebrows and we should think hard before calling. Most of the time we get checked to and can check back. Its also the way we would play if we had a big hand so it takes away a big bluff by villain on river (which could be what happened in this hand).

River: The turn was badugi so big hands could have checked knowing there is no flush draw possible coming in on the river. It sucks we hit our card and still are looking to fold but as many big bets are on the river... this is polarized. Comes down to what you know about villain which without any stats its hard to tell. You mention you think hes good which to me means a bluff is more possible here but not sure I would want to call so much with top pair and 9 kicker. If you were bluffed its a bluff that would get me too. Im folding here and not liking it but I think more often than not its the right play. I also think you could have played the hand differently to not put yourself in this spot.

Preflop
Even if LJ was limping a sort of capped and also wide range, raising K9o is likely not for value. In general I would also not expect him to do a lot of limp-folding, when he is this deep and in position. He did in fact end up folding, but unless you had seen him do this a lot, I think, this is to aggressive, and I prefer to just take a free flop and keep the pot small. ICM is fairly significant at this point, so there is definitely a lot of incentive to not play a big pot out of position against someone, who have you covered.

Flop
You flopped a gutshot, but even so your hand is not strong enough to call a check-raise and stack off. As a general rule of thump we should also be C-betting at a very low frequency on low connected boards. You have a ton of other hands, that want to check back this board, so I would also check this one back and basically try to realise some equity on the turn.

Turn
Not a good barrel card, so as played I would also check back.

River
The K is a good card for your range, and with the line, you took, he might put you on a hand like AK or KQ. Yet the opponent moves in for an overbet, and in my opinion its more likely, he does this, because he hope, you hit top pair and cant fold it, rather than because he is trying to buy the pot. It can be argued, that calling with K9 is better than say KJ, because you block the straight. But he can also have a ton of sets or two pair, that he might play like this, and its for all his chips and most of yours. So as played I would also fold here

Conclusion
If you keep the pot small, its easier to get to showdown with a marginal made hand, which is, what K9o will most commonly make. This is part of the reason, why its better to do some pot control on the early streets.

You had a note on LJ and using the exploitative strategy by raising this to 5bb, and if anyone make a call on you, you can sell it as an overpair probably and if not lay-down pre, lay-down this post flop. That was the pre idea if I'm not wrong.
However I think you have really deep stacks to consider a move like this with K9o, cause if anyone makes a call here the flop could usually not favour us that much to not turning this into a bluff only. In this spot for me even 810s is a better bluffing hand cause at least if someone does make a call on you, you are going to have some chance to not just outbluff this person, but hitting an actual dangerous combination. This risk you were going for was too much and not worth the risk-reward in my eyes.

As you could have your notes on them, they could have theirs on you. Out of position SB limp and called your 5bb bet, its something we may not take it very pleasant. Through your eyes as flop came, low flop definitely favour villain, and as I said, the only chance to us now to sell it as a premium pocket pair, otherwise its wasting of our chips, which we did already. When we were called, I think that was not an actual chance to win this pot, and even K did us a big favour, SB took the step and pushed to all-in. At this point I don't think there were weaker ones on villains hand so at least you could get away from this one.

In my eyes, don't be afraid of family pots this deep this position this hand, its made for them. And you can catch additional notes from the opponents, and not push your game to the limits.

Good luck!