1. Not all teachers are classroom teachers. For example, some are on-line teachers (as we all are, at least when we are here). Others are full-time on-line teachers. Private teachers who teacher one or two students, perhaps at the student's home, are not classroom teachers either.
Generally, there are other places where one can teach apart from the classroom.
2. Students who are used to acing exams saw raw scores of less than 60 percent.
"Students who are used to acing exams". Acing something (a metaphor from tennis and elsewhere) means doing very well at something. So this mean "Students who are used to doing very well in exams ..."
"saw raw scores of less than 60%." "Raw scores" are scores that have not been converted into a grade, such as A, E, fail, Credit, or whatever system exists. A "raw score" is the actual mark given.
So: "Students who are used to doing very well in exams are seeing (getting) scores of less than 60%". "Seeing" is confusing here. It simply means they are looking at their scores, and not liking what they are seeing.
60% is a low score for someone who is used to doing very well.