Welcome to the forum. You'll get some very different views on that - and some other issues - on here, so your best bet is to read them all and make up your own mind.
Personally, I believe that while in a perfect world dogs should not be left a full working day, that in some cases it is doable and not the end of the world.
I think it all depends on the dog (breed, age, individual personality) and the owner.
Dog:
Personally I wouldn't risk getting one of the high energy demanding breeds - collies and nworking breeds for example. These need lots of exercise and mental stimulation and tend to get bored very quickly. A lurcher or greyhound that wants to spend a large part of the day asleep anyway would probably be a better candidate for a working home.
Age - puppies need a huge amount of time, for training, socialisation etc. It is very difficult to provide a pup with what it needs if you work full time. Not to mention if a pup is stuck indoors from 9-5 every day it is unlikely to ever be housetrained and you will spend most of your evening cleaning up pooh and pee all over the place! An adult dog that is used to being left would be a far more sensible option.
Individual personality - not all dogs within a breed or age group are the same. If you would consider a second hand dog, then simply make it clear from the start that you need a dog that is happy to be left. It may be a high energy breed, or a youngster - so long as it does not suffer from SA and doesn't get bored too quick you may be ok.
Owner:
Don't just think about the length of time you are at work - what about everything else you have to do? Relax, cook, eat, shower, socialise etc. Bearing in mind how busy you are, do you still have time for walks, play, training, cuddles, grooming, vet trips, etc?
The best working homes tend to spend most of thier free time with their dogs - taking for walks in the early morning before being left, then again at night. Not leaving them to go out to dinner or the cinema after a working day etc.
Could you maybe hire a dog walker to take the dog outfor an hour during the day? Could a friend or family member pop round to give some fuss and let the dog out for a wee, or could you pop home at lunchtime?
Another thing - how long could you give the dog to settle in before leaving it a full day? If you want to get a dog friday night and leave it a full day on monday, then you are setting yourself up for trouble. If you ca take some holiday and gradually get the dog used to being left for increasing periods over say a few weeks, then you have a much higher chance of success.
There are a lot of things to consider, and it isn't something I would go into lightly - but with the right planning it can work. There are plenty of dogs left a full working day five days a week with no problems whatsoever - our first dog was one of them. You just have to be honest about what you really CAN provide, and finding a dog to match.