1:9 is typically used for heavier bullets and 1:16 for the 36-40gr.
I believe some of the older rifles (I've been told) had a 1:18 twist.
I am tempted to try a 1:9 twist on a 16 inch barrel, as I shoot 40 gr. subsonics mostly.
A 1:16 will stabilze 40 gr subsonics.
The most accurate ammo for my std carbine barrel is CCI subsonics.
Aguila 60 grain bullets keyholed out of my 1:16.
60's wouldn't do that out of a 1:9.
In a centerfire, too much twist on a light bullet with a thin copper jacket at a high velocity can cause such a high rotational velocity (~250,000-300,000 rpm) that causes the bullet to disintegrate as it leaves the barrel (sling apart). Can't imagine that happening in the low velocity of a 22 LR (~54,000 rpm for 1:16 vs. ~96,000 rpm for 1:9)
Hopefully a 1:9 barrel owner will chime in with why they have one, other than novelty.
Google "greenhill formula" for for info that you probably want on barrel twist.
I know you want a threaded barrel but i was going to but didnt because i dont want a supresser if u do go for it but if its for a muzzlebreak i wouldnt it makes the gun 5 to 10 DB LOUDER and the gas and lead shoots out the side or back depending on muzzlebreak so for a 22 the advantiges arent worth it other calibers sure. And about the twist ide say if your shooting 45 grain or less stick with 1:16 its overall better for reasons above the 1:9 for anything heavier for reasons above i shoot 32 grain varmit cci so a 1:16 twist is best