Trashed my X7 10 speed rear mech at Pivot 24/12 this weekend . Popped into my LBS on the way home but they only had an X7 9 speed mech.

The actuation is the same 1:1 according to blurb so will it work Ok?

There’s a mass of threads on here about it have a search. IIRC the threads are usually about a page of 50//50 yes no answers then about 2 pages of arguing. Road 9/10 is ok on sram, mtb isn’t but you may well get it to work but it won’t be perfect.

So if you’ve bought it already chuck it on see if it works, otherwise go buy the right one off CRC.