I agree with Willie. Also, if the price is right, maybe the trade-in value Leica offers for such an M9 against an M240 would more than offset the cost of acquiring it?
Would I get an M9 now? Having owned and used an M9 for four years and having acquired an M240 this year, I'd say one should take a long, hard look at the M240. While image quality (resolution) is not a big difference, and alone is not a reason for picking one over the other, the M240 is a much, much more refined camera in use. At least for my types of uses (such as events/weddings), its greater responsiveness is extremely noticeable and very welcome.
If you're not in a rush, chances are great that in the next 6-9 months we'll see announcement of the M240 replacement, which will further depress M240 resale value. As already noted, M240s can be found for relatively attractive prices. If the difference was only ~$1000 more for an M240, and I could justify it, that is what I'd get. FWIW, the M9 sensor problem is only a minor factor in my line of thinking.