the mistake you're making is that when he senses that you're leaving, you give him a toy or treat. this teaches him that if he acts up as you're leaving, he is rewarded by a toy or treat. the key to beating separation anxiety is COMPLETELY, and 100% avoiding them while leaving your house, or returning to your house. if the dog comes to the door as you get home, ignore him completely, no pets, don't make eye contact, or even talk to him until you have gotten home, hung up your jacket, took off your shoes, etc. and when you're leaving, don't say bye or give them a rub or a treat.

if you do, you are telling them that you leaving is a big deal that they should fuss about, because YOU fuss about it by giving them treats and pets and saying goodbye.

if the kitchen is doing well for him now, leave it at that before you try the crate again. he probably needs a little while to settle into his new (good) home before you will be successful with crate training.