If they don't confirm the lesson within three days and it has been confirmed automatically, no, they can't leave a rating or feedback. The only time they can leave a rating and/or a review is at the moment of confirmation.

I've never let a lesson confirmation just run its course, but since the teacher rating and comments screen is a pop-up that shows up after the class confirmation prompt, I don't think so. That said, I just have a student account and don't teach, so I don't know if the teachers/tutors here who take classes have different tools at their disposal.