Mountain Biking - XTR M950 rear derailleur compatibility

I've got an 8-speed drivetrain that I'm looking to upgrade to 9-speed since the my XTR shifters are broken and I'd rather not keep hunting down older 8-speed stuff. My question is, will the XTR M950 rear derailleur work with a 9-speed setup or were there limitations with the M950 that limited it to only eight speeds? I know the M952 and newer derailleurs were specifically designed for the newer setup as you could see "Mega 9" etched into the cage itself, but what about M950 rear?

Not to resurrect an old thread, but since there was no response to this one, thought I'd give it another go.

I also have an RD-M950 (medium cage) which I plan to use with an LX 9-speed shifter in a 1 x 9 setup with 32t up front and 11-34t in the back. My research shows conflicting opinions regarding using the RD-M950 with a 9 speed, maybe someone here can set the record straight.

I'd try it. As you know It's designed for an 8 speed chain, but if you have it indexed properly, It should work just fine.

I'd try it. As you know It's designed for an 8 speed chain, but if you have it indexed properly, It should work just fine.

+1. No problems as far as I know.

technically the derailleur is sposed to match the cassette, and since there are 8speed freehub bodies that are slightly shorter than 9speed bodies i would assume a 9 speed cassette is wider, However I think the derail should still have enough movement to cover all of that, I have an old 7speed rsx derail on my 9speed 11-32 tiagra cx bike and it works just fine, and thats not even a good derail, I imagine if I can do it with older lower end parts u'll be fine with xt.

Indexing occurs in the shifter, not the derailleur, so thats no problem. The derailleur can handle the range.. in fact I don't think the overall width is much different if at all.. but you may want to upgrade the pulleys to 9spd if thats possible, but it might not make a difference.

technically the derailleur is sposed to match the cassette, and since there are 8speed freehub bodies that are slightly shorter than 9speed bodies

This is incorrect

This is incorrect

+1. The width of 8sp and 9sp cassettes are the same, and the freehub bodies are likewise the same width.

9speed bodies work for 8 speed, but i replaced the freehub on my friends deore hub 4 days ago, and there where freehub bodies that work said 9 speed and ones that were shorter, I thought it said 8speed on it but its always possible it was a misslabled 7 speed