Newborn diapers

Lauren • Wife, J • 3.2017 💕 Mom, A • 7.2016 + A • 12.2018 + A • 8.2020 + A • 7.2022 💕
So baby is definitely going to be big, measuring 8 1/2 lbs at 38 weeks. If he's 9 1/2 lbs at birth, what's the likelihood of him fitting in Newborn diapers? I know they initially lose weight, but doesn't NB only go to 8lbs? I only bought 1 box of NB, I honestly thought he would be here by now.