I would definately get a crate.
It really is the best way to help your dog feel secure and safe while you are gone - plus keep him from destroying your house! Usually when a dog tears things up while you are gone, it's because he's feeling anxious. A crate will help calm him down.
You can make the crate a very positive, happy place. Our dog loves his! He's crated each morning while I go into work, everytime we leave the house, and overnight. There have been nights I've left him out, but he goes to his crate and sleeps in there until morning.

I give our dog those little freeze dried liver treats each time he goes into his crate. He loves those things and will run in there as soon as I say "get in your crate". I also leave him with a kong with a liver treat or two in it, or a spoonfull of peanut butter. Gives him something to chew on and play with. But honestly, he mostly sleeps when he's in there!
As far as length of time, I don't leave him more than 6 hours during the day. Most days it's 4-5. But to be honest, even when I've left him 6 hours he was just fine. Didn't have to pee that bad (waited a good 30-45 mins before even going!) and was fine. I guess 6 hours is just my personal limit, I think he could be in there longer and be ok - he's in there about 8 hours overnight.
But trust me - a crate will be your best friend! And your dog will learn to like it too. Another plus? When you have a maintenace guy over, or friends who are scared of dogs, etc - you can put your dog in the crate. Ours goes in there and does not whine, bark, etc, even when people are working in the house. It's great for everyone.