Sora beat the guy that looked like Terra in FM+ So i think he is stronger than Terra. Whether Xigbar fought the others himself or just watched he couldn't beat Sora either. I think Sora qualifies as a Keyblade Master. It doesn't matter how long you have been fighting just the amount of skill you have. Sora beat Squall, Cloud, Sephiroth, and many other Heartless and Nobodies. I think he has the skill to qualify as a master.
We don't even know if TAV's master wields a Keyblade...
We don't even know if TAV's master wields a Keyblade...