The vegetables should be perfectly fine to eat. They'll probably be mushy after 8 hours of cooking, but that's the only issue I can think of with them.

If you'd roasted the chicken, I'd tell you to keep the carcass to make stock out of. But 8 hours in a crock pot should have gelatinized all the cartilage and bone matter it could and cooked all the flavor out of it. Tossing the bones is fine at this point.