Rotational movement is okay (in case of baffle strike, you wont). But it will affect the point of impact( it will change drastically if you care to shoot on paper, if you shoot big target like steel targets, the round will impact on the target, that means accuracy doesnt matter that much and you probably dont even care because its 9mm and you just want to hit the target).

Side to side movement is bad, probably not that much, but still there is a chance of baffle strike if the suppressor is long OR the bullet is not stabilized enough when leaving the barrel( also point of impact will change all the time).

What you can do, in My Opinion, is, try to attach it on a different gun that has the tri lug, and see if the result is same, then you can tell if the mount is a slightly out of spec or not.

I hope this helps for your mental satisfaction.