Yes, but the carbon disc is surely an equivalent issue? I suspect it will work, but the OP would need to measure the derailleur clearance he has now, and see if he can move it ~5mm inboard. The cassette width difference is ~3.6mm.

This is the 11spd version.




Yes, machining the freehub could weaken it. If the conversion freehub will work, that's easy and not too expensive. But doesn't it look like about what you'd get by machining a 9spd freehub? Thinking the machined 11 spd cassette would be the better option, if there is clearance.