At 8 months old, you should not need pads.
While it's not ideal, you pup should be able to hold himself in his crate for that time. The best scenario is is you can have someone come home a lunchtime to let him out.
A compromise, which is what I've done for my pup, Bacca is to put his crate inside an Xpen. He still has limited access to the house (to avoid chewing) but can get up and stretch his legs and have a little water.
I still come home at lunch anyway, but there is the rare occasion when I cannot make it home. With this, I know that I've done the best that I can to keep him safe and comfortable.