I have 4 boxers.. 3 adults and 1 pup. They have their own room and a dog door that leads out to a large kennel. 2 of the adults are great, I could leave them home for days and they wouldn't do anything they weren't surposed to. However, the youngest of the adults is pure evil and will get into something if you turn your head and the puppy is just that. I am home with them all day and they sleep most of the time. They are also crate trained and have been left in them for up to 10 hours with no problems (not the puppy) so I guess it would all depend on if the PO did any training with the dog to begin with. But I would say that if you had a spot to put in a dog door to a kennel, thats the route I would go.
Also, if you are going to get him, do it on a friday (assuming you work during the week) that way you aren't bringing him home then just leaving him alone.