Welcome
Unfortunately you have to be patient.
You mention his kennel, is that a fenced area or a crate ?
If it is a crate, I only use them for night time.
I believe a dog needs room during the day.
When I go to work, I put my pups either in a bathroom or the laundry room.
He will get use to being alone, it does take time.
Give him a special toy, a chew bone (that keeps them busy).