I applaud your concern about getting a puppy when you are not able to be home during the day. Too many people don't properly think through the commitment needed to have a dog in their life.

That being said - It sounds to me like you have any almost perfect situation and are willing to do a great deal to make a pups life a good one! There are breeds that do very well being alone 8 - 9 hours a day and breeds that do not. I don't know much about Shibas so can't offer an opinion there, but Lovemyshiba will probably be around and give you more insight on the breed.

Having a gated area is perfect, but if you are unable to be home you are going to need to put papers or puppy pads down in an area and train them to use them when you are not home. Puppies generally can't hold it more that a couple of hours at first. I would also recommend crate training with a strict schedule the first couple of months. Something like this:

First thing in the morning - immediately take outside/paper for potty. Does both - PRAISE GREATLY then playtime. Doesn't do both - keep on the lead with you - feed and water. (I suggest feeding in the crate - Great things come in crates)

Before you leave for work - another trip outside/papers. Again praise greatly

Put in play area with lots of toys. Chew toys especially. Have a crate in the opposite area of the puppy pads. Put a piece of your clothing in the crate. The sweatier the better. Normally I would recommend putting them in the crate while you are at work, but 8 hours would be too long to hold it. If you can get someone to come over and take the dog out at noon and play with it, I would say crate the pup. But if not, a closed off area is also good.

First thing when you come home. Take the pup out for potty. Does both - Food and water and playtime for about 30 - 45 minutes then crate.

7:30pm last water. Take pup ouside/papers for potty. If he pottys - Play time. Then crate. If not keep on a lead with you and try again in a half hour or so. If the pup is especially thirsty and ice cube after that is okay. Obviously you have to be flexible on extra hot days and give them water later, but expect to get up in the middle of the night for a trip to the outside, or needing to go on the papers.

Right before bed - Take pup outside/papers for potty. Crate for the night. I would put the crate next to your bed. More than likely you will need to get up at some point to take out/papers, but they will be able to hold it for the night after a few weeks or so.

Don't forget PRAISE GREATLY every time the pup does what you want it to do.

Good Luck - and remember if you do get a pup, make sure you get from a reputable breeder and not a puppy mill or pet shop.