He's was probably bored all day and super excited to see you. I don't think it's bad to let the dogs have some alone time. Both my husband and I work, so our dogs are alone during the day sometimes. My husband has rotating shifts so he's sometimes home during the day. There is a deffinate difference in behavior on the weeks that both of us are gone all day. My dogs dig and chew more and are super hyper when I see them. I feel guilty about it, but at least they have eachother to play with.