OP - we have a rescue dog (staffy cross) and we both work full-time. However, our dc are home from school by 4pm and dh works odd hours so usually the longest she is left is about 6 hours, and that is usually in our enclosed garden, where she has a kennel (heated if the weather is extremely cold).
If we're going to be out for longer, we arrange for someone to either walk her, or just give her some company. Very rarely, she has been left for longer, and she's been fine - not ideal, but it's been ok.
Dh chose our dog, and went for her because she was calm. The neighbours report she seems happy when she's outside. She will bark if a stranger approaches (which is good), but doesn't bark all day for no reason. We walk her once a day, either in the morning or after work.
I agree with the poster who said thousands of dogs are left during the day, and it's better than them being put down or in a rescue centre.
However, the dog you choose is crucial and there's no doubt it's a gamble - it's no good if it's going to wreck the house or annoy the neighbours by barking... the tale here about the German Shepherd threatening a tenancy is a case in point.
Tbh if it had been up to me, I wouldn't have had a dog as I thought our lifestyle was incompatible, but dh always had dogs as a child and was confident it would be fine, and it has been. My condition (harsh as this is), was that the dog would come on trial, and if it didn't work out, she would have to go back. Not sure I could've lived up to that though!
Bear in mind that however much your dc say they will help, the novelty will wear off and it'll be you that does the work! That means feeding, walking, cleaning up dog hair and poop from your garden - think hard about that before you cave in! How will that be when you go back to work?
The Dogs Trust or similar wouldn't have contemplated us if we'd said we would be out all day, so she came from a small animal rescue centre.