The Soloist
Hero
In 87, the term Mage had replaced Magic-User in AD&D 2e. Mages are generalists, while Wizards could specialize according to a limited number of spheres but gained boons. Level titles had also been dropped.True, but were there even wizards? I thought they were called Magic Users. Then again, there was a list of titles for your magic user depending on what level they were and think sorcerer and wizard were on that list. I'm too lazy to get up off the couch and check.
But the show's D&D is AD&D 1e. So, yes, you are correct, a Magic-User level 9 is called a Sorcerer. It's not a mistake.