Can any MTB rear derailleur be mounted to a Scott type 1 MTB derailleur hanger? Can any Shimano MTB rear derailleur be mounted to a type 1 (206375) Scott derailleur hanger.

I have a type 1 derailleur hanger with a Shimano STX rear derailleur mounted and like to mount a Shimano XT rear derailleur:






The reason I ask is, because last year I wanted to temporarily replace my derailleur with a Shimano Alivio 8 speed derailleur because the old one was damaged, but I had problems mounting the derailleur in the correct position/angle. I was able to screw it tight, but only in a strage direction. I finally gave up and managed to repair my old derailleur faster then expected.

Now I'd like to upgrade to a 9 speed cassette, gearshift and rear derailleur and remembering that problem back then makes me ask the same question again.

Products in question:


https://www.bike-components.de/en/Scott/Ausfallenden-Schaltaugen-p30245/ (type 1: last photo)
https://www.bike-components.de/en/Shimano/XT-Schaltwerk-Shadow-RD-M772-9-fach-p16320/
The thread on a derailleur fixing bolt is typically 10mm x 1mm thread pitch.  For almost any standard derailleur, that will be correct. 

There are a few very new designs on the market which might not fit, namely Shimano's new direct mount derailleur system, but that would be a special order in most shops at this stage.  

Anything on the market for 9 speed mountain should fit a 10 x 1 thread.

So to answer your question:

Technically, no, not any derailleur will mount to your Scott derailleur hanger.

As a practical matter, yes, you are pretty safe ordering any 9 speed MTB derailleur, and it will work.  And if it looks like the same mount, it will be. 

That said, it sounds like you may have cross threaded your derailleur hanger when you tried to change it the first time, so you may also want to pick up a spare derailleur hanger.