Well, it is not a MK9 extruder, I just called it MK9.
This is my Makerbot Thing-o-Matic, and I had problems with my MK6+
and I had a broken mk7 extruder (it was a fake). So I combined thefillament guide with the mk6 nozzle. Instead of a NEMA 23, there is a NEMA 17 stepper motor, and it works with the standart options of MK6 (0.5mm)