Used to be a 609...
...but was changed to section 709 when they re-indexed the original FAA authorization act.
As far as the 709, it is not always a standard procedure. If you are a CFI and were with a student, then you can expect a 709.
By the way, you do not have to take the 709 with the FSDO that is investigating the incident. You can go to any FSDO and schedule the ride.
Most importantly, if you plan on a career in aviation, I would talk with an aviation attorney. If you belong to AOPA, I think it's free (or at least available at a reduced cost).
Believe it or not, there may be some good news here. Typically, after completing the 709 (successfully), you should not face any further discipline. The FAA usually chooses between two routes: enforcement or competency. In the case of the 709, they seem to be choosing the later.
I would talk to an attorney however (to verify everything I'm telling you).
Good luck!