Can I use a XTR M9000 power meter on a XTR M9100 crankset?

Great question! Unfortunately the answer is no. Shimano changed the spline depth on the Mx100 series. Therefore you would need a XTR M9100 specific power meter.

We have a separate article that explains all of your XTR M9100 power meter options: What power meter will fit my Shimano XTR MTB crankset?