From what I understand the clutch of MY07 and MY09 are different. I need a 16T driver which I can only locate for a MY09/X30. Would the solution be to swap the crank to MY09 and by a16T for a MY09/X30?
No, the MY07 and MY09 have different crank shaft diameters. Since the clutch bell uses the Driver as the point of rotation, you will need to find a driver for that crank. I believe the largest driver they sell is a 12 tooth. What is your application that you cannot change the driven sprocket to get your desired ratio?
Road racing at car tracks requires a 16T
So I just went back and looked up the part numbers for the roller bearing on the drive sprocket. They are very similar. If I were you, I would contact Comet Kart Sales (317.462.3413) and ask to talk to one of their Gurus. You may be able to swap out clutch bells and drive sprockets with no other change.
The MY09 crank is a bigger diameter at the bearings. However, I think once it is tapered down for the clutch they may be the same diameter at the clutch bell.
Also, ask on the Enduro Go-Kart Racing facebook page, somethere might be able to help.