This gets a 9 from me simply because the romance goes beyond the will they / won't they, which already puts it ahead of 95% of romance anime. The characters are drawn well, and the voice acting is enjoyable in the sub.
The MC has no character and is drawn like a wet noodle, but his relationship with the romantic interest is engaging and the background story is interesting. The supporting cast really goes a long way to elevate this series.
The love story is teacher/student and it really didn't need to be, since the story doesn't really leverage this taboo.
If you like this, you need to watch Ano Natsu de Matteru.