Akin to Whitesnake, which is considered sentient, Under world can act and speak independently of Donatello (As seen when it points out Jolyne's entrance into the hole, to which Donatello didn't seem to notice himself). I think it would make sense for it to be listed as sentient, it can be remotely controlled at times, but so can Whitesnake. I feel like in that regard they function the same.
Personally I don't think so as most of the time the stand just takes orders from Versus. The one instance where it speaks for itself isn't really enough to justify changing the label. Whitesnake is seen talking and acting on Pucci's behalf in a lot of scenes, but since Underworld only does so once, its probably just a one time thing.
»Personally I don't think so as most of the time the stand just takes orders from Versus. The one instance where it speaks for itself isn't really enough to justify changing the label. Whitesnake is seen talking and acting on Pucci's behalf in a lot of scenes, but since Underworld only does so once, its probably just a one time thing. «