$50 NL HU - Top pair, weak kicker. Line check?

[octaveshift]

***** Hand History for Game 2450770882 *****
$50 NL Texas Hold'em - Saturday, July 30, 19:37:11 EDT 2005
Table Table 37195 (Real Money)
Seat 6 is the button
Total number of players : 2
Seat 6: john1472 ( $50.85 )
Seat 9: xyrophobic ( $46.45 )
xyrophobic posts small blind [$0.25].
john1472 posts big blind [$0.50].
** Dealing down cards **
Dealt to xyrophobic [ 9d Kd ]
xyrophobic raises [$1.75].
john1472 calls [$1.50].
** Dealing Flop ** [ 3c, Kh, 6d ]
xyrophobic bets [$2].
john1472 raises [$4].
xyrophobic calls [$2].
** Dealing Turn ** [ 6c ]
xyrophobic bets [$5].
john1472 raises [$10].
xyrophobic calls [$5].
** Dealing River ** [ 3d ]
xyrophobic checks.
john1472 bets [$20].
xyrophobic ???

Call the river?