It could, the relevant part of the whole thing is the object's mass (and therefore its gravitational influence) and its orbit.
Lex Fridman did a podcast interview a few months ago with Konstantin Batygin [0] about the topic of Planet Nine and he poses this exact question of whether or not it could be a black hole [1].
More specifically, he asks if it could be a primordial black hole which would make it a double discovery since primordial black holes are still only theoretical.
