I hope you aren't leaving him all day. An 8 week old should be able to go 4-5 hours in a crate, but likely not all day. They also need a mid day meal until 3 months old. If you must leave him over 4-5 hours, try to find a neighbor or professional dog walker to give him a break. With a break, you can leave him in the crate and not use the restroom and baby gate. Stick to feeding dry food.
For more information see the sticky starting at
https://www.askmehelpdesk.com/dogs/i...tml#post251802