Very interesting information and truly a great time to be a photographer.
The best real world comparison for me would be to photograph the same scene or test setup, at least as close as reasonably possible, using say a 50mm on the M9 and a 35mm on the Sony. Use comparable lenses of comparable vintage and process using your best techniques and print at 16x20 and 24x36 and examine the results of the prints. This would provide a real world comparison of how I could capture and print the same scene with each camera and what difference in results I might expect. As I don't currently have access to either camera I will leave this to others!