50NL - back to back hands, did I leave value on the table?

Same villain both hands, 90/20 over 55 hands, we hadn't interacted much at this point. He showed down crap hands, and tended to be very aggressive at every act of weakness. He also liked to min-raise, often with very marginal hands/draws.

PokerStars No-Limit Hold'em, $0.50 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($71.05)
UTG ($160.25)
MP ($45.50)
Button ($27.60)
SB ($162.90)

Preflop: Hero is BB with 9, 8.
UTG calls $0.50, MP calls $0.50, 2 folds, Hero checks.

Flop: ($1.75) 5, 7, 4 (3 players)
Hero bets $2, UTG calls $2, MP folds.

Turn: ($5.75) 6 (2 players)
Hero bets $3.5, UTG calls $3.50.

River: ($12.75) T (2 players)
Hero checks, UTG bets $13.5, Hero calls $13.50.

I like to take stabs at limped pots; to build a pot if I have any chance of making a strong hand, because it's cheap, because people often give up easily.

PokerStars No-Limit Hold'em, $0.50 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($89.35)
BB ($140.75)
UTG ($45)
MP ($27.60)
Button ($162.65)

Preflop: Hero is SB with A, A.
3 folds, Hero raises to $2, BB calls $1.50.

Flop: ($4) 7, 9, 7 (2 players)
Hero bets $3, BB raises to $6, Hero raises to $18, BB calls $12.

Turn: ($40) K (2 players)
Hero bets $20, BB calls $20.

River: ($80) 7 (2 players)
Hero checks, BB checks.

Flop, Maybe he has a 7, I want to find out now.
Turn bet, is 1/3 of my remaining stack (villain has me covered).
River I hoped for a river bet after I checked. I should have pushed I think.

Any thoughts are appreciated.

1st hand.... anything but check/calling the river....... man this is bad. you lose to a backdoor diamond draw and thats it.

2nd hand.... you should probably leave off results (how he checked back the river), but regardless, I also think this is very bad. You say you hope for a river bet after you check (I assume with the intention of calling if he sticks it in), but why not just put it in yourself? I think it's very clear that he will call with a wider range then he'll push with himself, so just put it in yourself.

BTW, I think the flop play is good against most opponents.

I agree with Lukie... just wanted to add that in Hand 1 you have to pot the turn. Gotta build the pot,esp. against bad opponents. I like a river c/r in Hand 1 and a bigger turn bet in Hand 2