[Jeff Lee]

Time is driving you nuts? Welcome to the club! If your just picking up the car from MOPAR in October, unless your a super-hero assembler or have a dedicated crew with nothing else to do for 60 hours a week, there's no way you can be racing inside of three months. I'm assuming paint, wiring, blue-printing, etc. If I'm wrong, go for it and good luck.
But if I'm right, after reality sets in, you should have plenty of time to get the right trans, whether it be an auto-trans (Pro-Trans) or manual (Jerico, G-Force or new liberty soon to be released). Do it right the first time. Having such a car that will be under a microscope by everybody at the track does not deserve second hand parts.
And as mentioned, call Advanced. They'll set you up with the Bellhousing, trans and clutch. Like I said, do it right the first time. The fact (?) nobody has run an '09 Challenger with a stick means nothing. If your the first and get it down the track quick you may get more ink and therefore maybe a sponsor.
Have fun!