How good is an underboat in this game?

[elitegimp]

A little disclaimer (in four parts):
(1) I'm very interested in learning to play O/8, but I'm extremely bad at this game
(2) I'm mostly concerned with my river play, but I doubt I played any of the other streets correctly (okay, maybe the flop was right [img]/images/graemlins/tongue.gif[/img])
(3) I'm converting by hand, hopefully it'll be readable
(4) I've been drinking a little tonight

No reads (see #4), Limit O/8 ($0.50 / $1), 9-handed

Hero is MP2 with 9 [img]/images/graemlins/heart.gif[/img] 9 [img]/images/graemlins/spade.gif[/img] 5 [img]/images/graemlins/diamond.gif[/img] 3 [img]/images/graemlins/diamond.gif[/img]

Preflop:
UTG calls, UTG+1 folds, MP1 folds, Hero calls, MP3 calls, CO calls, Button folds, SB calls, BB checks

Flop (6 players, 6 SB): 9 [img]/images/graemlins/club.gif[/img] 7 [img]/images/graemlins/club.gif[/img] K [img]/images/graemlins/diamond.gif[/img]
SB checks, BB bets, UTG calls, Hero raises, MP3 calls, CO folds, SB calls, BB calss, UTG calls

Turn (5 players, 8 BB): J [img]/images/graemlins/spade.gif[/img]
SB checks, BB checks, UTG checks, Hero checks, MP3 bets, SB raises, BB folds, UTG calls, Hero calls, MP3 3-bets, SB calls, UTG calls, Hero calls

River (4 players, 20 BB): J [img]/images/graemlins/diamond.gif[/img]
SB checks, UTG checks, Hero checks, MP3 bets, SB calls, UTG calls, Hero calls

Final Pot: 24 BB

So after the turn action, it looked like I was up against 1 (or 2) straights, but I thought I had 10 outs to fill up and beat the straights. Once I filled up on the river, though, I started wondering why UTG was cold-calling, and was suddenly afraid of him having KJ or J7 (J9 was possible too, I suppose, but very unlikely given my hand and the board).

So on to my question (in two parts):
(1) Should I really be seeing the river with this hand?
(2) If so, what is the proper river action given that I have an underboat?

Like I said, I'm new to this game and [clearly] not very good... so brutal honesty about how bad I am is expected (and accepted).