NL50 - having trouble in a standard spot

[Ramana]

No reads on villain except that he's been betting and raising quite a bit, but showed goods hands each time.

Why am I raising this flop? Is it for value? Is it because I want to protect from draws? Should I not call his push then? In case I don't put him on a draw or on a weaker hand, does it not make sense to call his flop pot-bet and reevaluate turn? It is a very simple hand, but it really bothers me, because I don't fully understand what I did there.

Prima Network No-Limit Hold'em, $0.50 BB (5 handed) Hand History converter Courtesy of PokerZion.com

BB ($50.52)
Hero ($103.86)
MP ($50.00)
Button ($62.07)
SB ($19.77)

Preflop: Hero is UTG with 9[img]/images/graemlins/club.gif[/img], A[img]/images/graemlins/club.gif[/img].
<font color="#CC3333">Hero raises to $2</font>, <font color="#666666">3 folds</font>, BB calls $1.50.

Flop: ($4.25) 6[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $4.25</font>, <font color="#CC3333">Hero raises to $13.5</font>, <font color="#CC3333">BB raises to $48.52 (All-In)</font>, Hero ???