I work full time and my husband works for 8 months of the year. For the four months when he doesn't work, the dogs get used to having him there pretty much round the clock. When he goes back to work they revert to being alone for about 9 hours, 3 or 4 days a week depending on how our shifts fall. They seem to just adapt, they have a lot of exercise and attention when we are there and I have never seen any sign that they are in any way stressed when things change.
I think the handmade dog treats might be a hard act to follow though