Oh, I can't wait to see the pics of your adorable little boy and read all about your trip. I think with 9.2 lbs at 8 weeks he is probably going to be daddy's size. They say to take the weight at 8 weeks and mulitply it by four and that's about the adult size of your dog. So your little boy should be 36.8 lbs. It will be interesting to see if how off the formula is.
How big is his mom and have you seen the grandparents?