I'd definitely wait till the puppy is at least 12 wks old. A colleague of mine bought a JR puppy a few months back. The puppy was only 8 wks old when he brought her home. I told him maybe he should wait but the breeder sound like she just wanted to get rid of the puppy
We visited Sandy at our breeder's a week before we took him home. He was 11 weeks old back then. He was paper trained. We watched him going to the paper and did his #2 there. Both of us were like WOW!