Why did he Push this river?

[I-Love-Poker]

Can any1 explain this?

Full Tilt Poker Game #4253449073: Table Manor (heads up) - $25/$50 - No Limit Hold'em - 20:26:36 ET - 2007/11/21
Seat 1: TimeServed ($14,731.75)
Seat 2: Boosted J ($5,000)
Boosted J posts the small blind of $25
TimeServed posts the big blind of $50
The button is in seat #2
*** HOLE CARDS ***
Boosted J raises to $150
TimeServed raises to $450
Boosted J calls $300
*** FLOP *** [Qd 9d 4s]
TimeServed bets $800
Boosted J calls $800
*** TURN *** [Qd 9d 4s] [4d]
TimeServed checks
Boosted J bets $1,350
TimeServed calls $1,350
*** RIVER *** [Qd 9d 4s 4d] [9c]
TimeServed checks
Boosted J bets $2,400, and is all in
TimeServed has 15 seconds left to act
TimeServed: the one card i did't want to see
TimeServed has requested TIME
IDONTPLAYSHTY (Observer): lmao
IDONTPLAYSHTY (Observer): four or flush?
TimeServed calls $2,400
*** SHOW DOWN ***
Boosted J shows [Qc Ac] two pair, Queens and Nines
TimeServed shows [As Ad] two pair, Aces and Nines
TimeServed wins the pot ($9,999.50) with two pair, Aces and Nines
Boosted J is sitting out
*** SUMMARY ***
Total pot $10,000 | Rake $0.50
Board: [Qd 9d 4s 4d 9c]
Seat 1: TimeServed (big blind) showed [As Ad] and won ($9,999.50) with two pair, Aces and Nines
Seat 2: Boosted J (small blind) showed [Qc Ac] and lost with two pair, Queens and Nines