Yes, drifter has less bottom end, 9m Drifter would be similar to 8m SB, I have 7,9 drifter and have had 9,11 SB, always found SB to be much gruntier, perhaps 1-1.25 m more power. 9m drifter will kick in at around 17 knots and go up above 25 knots.

So sounds like 9m is your ideal.