I am currently encountering this very same thing with Bijou, as long as he can see me he is fine, if not he starts to make a racket and bang and scratch. I try to ignore it as it will only encourage him that everytime he kicks up a stink I will rush to him. Bandit was like that and now he can care less if I stay or go out the door
...I think it takes time, when they know you will be back they will quiet down. DONT GIVE in to him.
Cover the crate it works