I believe that a full grown saint would do fine with your schedule. A puppy, however, cannot go that long. If you cannot come home from work, you could see if a neighbor, friend, or relative can walk the pup, (not just let it out to pee, but actually take it on a 20-30 minute walk, multiple times a day) or else you would have to hire a dog walking service. You cannot take a puppy to doggy daycare, at least not for the first few months. First, the puppy has to be old enough to have all of its vaccinations before it is safe to be near strange dogs, and second because many doggydaycares will not take pups who aren't potty trained.
I think that saints are wonderful dogs, and I don't neccessarily think that your work schedule would be a problem as long as you plan to give them lots of love and attention after work. But unless you can get someone to take out a puppy every other hour, I would suggest looking into rescuing a grown saint.