Welcome! Nice Super 9.
Yeah, the RSII would be better for sure. I'm revving my stock crank to 12,000 RPM plus, but I can not yet speak for it's longevity as I not quite finished my build. The Kymco cranks are pretty tough though. They have thrust washers, good lubrication to the bearings, and are robust overall. I know that on the Zuma engine the crank is a concern, but I don't think you really need to worry much about your Kymco crank unless it's been though some really rough times or high milage.
Looks like custom paint on your scoot?
Zuma is cool too. Is the wiring going up to a tach or GPS?
~Josh