We have a Cockapoo, both leave the house for 9 hours a day, the dog is fine. I overthought it too before we got one. Just make sure the room the dog is going to stay in has tiles on the floor and nothing you don’t want chewed to pieces. It takes longer to house train a dog when no-one is there, but the dog will learn.
Most importantly, research the breed, get the right dog!!!!! Head over heart!!!!!