I'll give you a 10 on this one. Fill up every single line and write with a simpler language (but with a richer vocabulary). Reading through your essay, I didn't pick up your thesis very well, so you might want to consider highlighting it, aka. make it more noticable.
For your reference, Martin Luther was not a 10th century dude. Rather the 15th-16th, while you can't be penalized for factual errors, such obvious ones can turn off your readers. As SAT essay readers only get to read your essay once and will spend about 2-3 minutes reading it, you don't want to give them a bad impression.