I think the difference in how the chainrings are spaced came with 11 speed. I know I used 9 Speed chainrings with 10 speed and vice versa. Then again, that was awhile ago, for sure I used 10 speed chainrings with 9 speed drive train. The one difference in 9 to 10 speed is the 10 speed front derailure has a small plastic spacer you can remove if you want to use it on 9 speed (besides the obvious 9 vs 10 cogs, and the rear shifter has an extra click with corresponding spacing for each click). I still use my 9 speed front derailure on my 10 speed bike, shifts like butter still no need for the spacer.