First of all, your dog has to be crate trained. This means he needs to be in there for short periods of time, gradually increasing the time little by little so that he gets comfortable being alone in the crate. (ie: 10 min alone, 20 min, 30 min, 1 hour, etc) then rewarded extensively for not barking/whining and for relaxing in the crate. Be sure he has a chew toy in there to keep him busy.
If you choose to crate train your dog, then by all means have him in the crate during the day, it should not be a problem because he is crate trained and finds his crate to be his "den", his place of comfort.
If he has a smaller bladder (which most puppies do) it's best to have someone to come in the middle of the day to take him outside, but this will not be necessary once he grows up and is able to hold his pee for the whole day.
Don't leave anything in there that you don't want a dog to be able to chew on, including blankets, until he is trustworthy enough NOT to chew on them. It's best to prevent a habit BEFORE it happens, rather than to try to change a habit after it is formed.
If you did not crate train your dog, my solution would be to buy a doggy gate or playpen that you can secure very firmly to the wall. Test it to make sure it will not fall if pushed/jumped on. Make sure it is tall enough so your dog cannot easily jump over it. Attach it to the walls around his crate and leave some chew toys to keep your dog occupied. Put in a dog bed and a water bowl and lots of toys! This way he will not feel trapped inside the box that he was not trained to love yet.
Same rule applies about taking him out in the middle of the day if he is still young!
Hm, I think I would have a dog walker come by mid day to break up the 8 hour crating. 8 hours is on the long end. I'd consider hiring a dog walker until you can trust him to roam free in your home.
Hi, My dog Oscar is getting out of the house four times a day, at least 30 minutes, every time. I do it myself, I can do that, working as a freelancer at home. If I couldn't, I wouldn't let him stay indoors for more than 4, 5 hours. I would hire people for walks. No crates ever for ever for Oscar.