@Minigiant and @dnd4vr - The folks I played D&D and WoD with never had trouble with nine. Y'all ever have trouble with folks moving from D&D over adjusting to more stats?
My own custom Urban Fantasy game uses the 8 stats I suggested. The players had no problem with it but the setting and system wasn't D&D like.
The physical bonuses worked the same. Replace crossbows with guns.
The mental stats worked different because most mages were wizards, sorcerers, warlocks, druids, artificers, and clerics at the same time.