Your 2009 use year points are used for stays October 1, 2009-September 30, 2010. Technically, the points are already there for you to make reservations for stays that occur between those dates. Your 2010 use year points are also already there, but for trips that happen between October 1, 2010-September 30, 2011. It is possible to make reservations in two different use years at the same time.
For a trip in November of '09 you can use all of your August '09 points plus any '10 points you might need to complete that ressie. You can call to make it this December 11 months from your check in day, and you can book up to the first 7 nights with that one call.