So it appears in the Beta your starting subclass is not locked. The level of your character is still locked at 8 but I am still gaining abilities in my subclass. I have already gained 3 abilities that I didn't get in the Alpha because the subclasses where capped. This excites me very much as I now will be able to unlock triple jump for my Hunter eventually it seems :D I will update this post if I stop gaining xp in my subclass.