Wow, great analysis futurefreak. Totally redeems the bump
Actually, your first option is what was going on. For Bender to maximize profit as a bookie, he want most everybody to lose. Anybody placing a bet will probably bet for one of the lowest rounds, so if Fry can somehow make it to the 9th round and take a dive, then Bender makes glorious returns on everybody else's money.
However, to digress, this theory seems to suggest that Bender isn't very good on gambling. If Bender honestly believes that Fry can even make it through 9 rounds, then he's a poor statistician and he's very bad at guessing the outcome whatsoever. These are horrible qualities for bookies to have. Everything seems to suggest that Zoidberg will
win in the early rounds, because he has all the advantages. Furthermore, this scene is taylored to boxing, which employs the usage of rounds. It's highly debateable that Claw Plaque even has rounds (despite Zoidberg's comment)... it's a battle to the death... Bender could be out to lose very big in this whole affair.