I'm gonna through this out there, though I wouldn't recommend that people trade options (I don't myself). I think they can make sense in some situations as insurance on existing positions or as cheap spec plays, but I think there's a lot of potential for people to be taken advantage of by the professionals that really see what's going on and trade options for a living. That said...
If people really think FB might be going to $9 - that there's a meaningful chance that will happen - the market is offering them ways to make big returns on relatively small bets. The ask on a September 2012 put option with a strike price of $15 is now $0.25. A put option is the right to sell someone the underlying stock at the strike price on or before the expiration date. So, for 25 cents, you could buy the right to sell someone FB stock for $15 before September 2012 (it's actually a specific date in September, I don't recall which day is used).
What that means is this: You pay 25 cents per share (e.g. 1000 put options cost you $250). That's your total exposure - the most you can lose (aside from the transaction fees). If the stock never dips below $15 before September 2102, you're out that initial expense. But if the stock dips below $15 at any point between now and September, you can buy it for the market price and sell it to the person from whom you bought the put option for $15. In other words, if the stock drops below $14.75 (it doesn't need to end up there in September, it just needs to drop that low at some point in the meantime) you end up making money (minus transaction fees). Everything below that $14.75 is profit - if it drops to $9, you can make $5.75 / share (e.g. $5,750 on those 1000 put options that cost you $250).
I suppose the takeaway is that the market - the people that put their money where their mouths are - thinks there's very little chance that Facebook will drop that low anytime soon. If someone thinks there's even a 1 in 20 chance that FB will hit $9 over the next few months, this is a great bet - and you don't even need it to go that low in order to make money, you'd make some money (just not as much - only about 3 times your initial investment) if it went to $14.
There are similar put options for a $10 strike price, $11 strike price, $20 strike price, etc. There are also put options that expire in June 2012, January 2014, etc. The current ask on a September 2012 put option with a strike price of $20 is $0.85 - that put option makes money if FB falls to $19 and a lot of money if it falls to $9 or even $15. For 85 cents per share, you could make $10 per share should the stock drop to $9.
Anyway, again, I'm not suggesting that people get involved in the options market. But if someone really thinks this stock is going into the dumper, there's room for them to make a lot of money with relatively small risk (i.e. a smallish amount of money being risked). The market certainly gets things wrong sometimes, but it isn't too concerned about Facebook falling that low.