I think (as I've never bough an airliner...) it's a case of there being a date on the options, when they must either have been converted to a full order or they expire and the airframer can resell them.
FCA were an early buyer so their options may be valuable, as they would be for aircraft early in the production series compared to people turning up today wanting some. If they have options for 2009 deliveries, you couldn't go to Boeing today and buy them as they have a full book for a few years out.
That's assuming no slippage in the program, which is by no means certain. New buyers might have to wait until 2012 or later.