I'd get him used to being away from you. Like when you are home, baby gate him in a different room, where he can see you while you do some chores. Start by doing this for only 5-10 minutes at a time but frequently. Slowly increase the amount of time & distance that you are away from him.

Try putting something ultra yummy in his kong. LIke left over mashed potatoes with meat chuncks or whatever he is really fond of.