Weapon Mastery passive skill

Hello!
I have learned Weapon Mastery (x3) in skill tree. I use only melee atacking skills (no range shooting). Do I still have bonus of x15 increased critical damage (from Crossbows) or only x9 increased damage (from swords)? So I don’t use crossbow and carring it to have stats and aspect.
And second question:
If I’m using two swords, does bonus for swords from Weapon Mastery doubles? Example: 3 skills in WM gives x9 increased damage for each sword (total x18) or x9 in total? If only x9 - then it’s more useful to use one sword and one dagger to have both bonuses (x9 incr.dam. from sword and x15 incr.dam. to Healthy enemies from dagger).