Johnny 5 was sentient, yes. He was a robot, yes.
Was he human shaped? In my opinion, yes. Now you could argue whether it was a gynoid or an android, but based on his appreciation of the Alley Sheedy in the bath, I'd say he had a male mentality. While you are quite correct in that he was not exactly humanoid shaped, but certainly based on a nearly vertical posture, two arms, two hands, binocular vision he was far closer to human than R2D2.
While we can say that he was a robot, I would be inclined to say he was also an android.
Not all androids would be as perfect as Commander Data or Six, in terms of human shape emulation.