Not a big deal. The head weights should progress by 7 grams (9 being 7 grams heavier than the 8). There could be +-a few grams tolerance on heads. Assuming a 1/2 difference in shaft lengths at your playing lengths, a 1/2″ of graphite shaft weighs less than 1 gram. Also, grip weight tolerances of +- 2 grams should be considered. So, in short, they should be a little different weight when using a parallel tip shaft that is tip and butt trimmed, but not that much and with the acceptable component tolerances, they could be close to the same weight.
Britt Lindsey