River play question, but could use critique on all streets

[Under Control]

***** Hand History for Game 829511296 *****
Table Table 14200 (6 max) (Real Money)
Seat 5 is the button
Total number of players : 6
Seat 8: alonsito ( $39.4 )
Seat 1: Hero ( $119.7 )
Seat 10: kennykaren ( $126.25 )
Seat 6: marino03 ( $95.65 )
Seat 3: vinman70 ( $11.4 )
Seat 5: onewildcard ( $49.6 )
>You have options at Table 14217 (6 max) Table!.
kennykaren posts small blind [$0.5].
Hero posts big blind [$1].
** Dealing down cards **
Dealt to Hero [ Qs 9s ]
vinman70 folds.
onewildcard calls [$1].
alonsito calls [$1].
kennykaren calls [$0.5].
Hero checks.
** Dealing Flop ** [ As, 6s, Kc ]
kennykaren bets [$1].
Hero raises [$4].
onewildcard calls [$4].
>You have options at Table 14217 (6 max) Table!.
alonsito calls [$4].
kennykaren calls [$3].
** Dealing Turn ** [ 2s ]
kennykaren checks.
Hero bets [$15].
onewildcard calls [$15].
alonsito calls [$15].
kennykaren folds.
** Dealing River ** [ Ad ]
Hero bets [$30].
onewildcard folds.
alonsito is all-In.

Results in white:

<font color="white">Hero shows [ Qs, 9s ] a flush, ace high.
alonsito shows [ 6c, 6d ] a full house, Sixes full of aces.
&gt;You have options at Table 14217 (6 max) Table!.
Hero wins $10.60 from side pot #1 with a flush, ace high.
alonsito wins $101.80 from the main pot with a full house, Sixes full of aces.
vinman70 has left the table. </font>

After the turn I was just glad to have hit my flush, and after the river when the board paired, I made the final bet without much thinking. Without some horrible opponents (2 callers, one of them has to be good), I think its very reasonable to suspect A6 A2 22 or 66 from at least one of them, but would I have to call them anyway with the pot being that big? I think I can put one of them on a lower flush but there is no other hand that explains those turn calls.

Now that I look at it, I am getting 3:1 on my money and I think 1 out of 3 times there will be a lower flush and a moron, so I think this river bet was ok. Anyone disagree? Was the flop semibluff bad?