To include more students in the PSAT experience, the College Board has created versions of the redesigned PSAT for different grade levels. While all exams use the same scoring scale, only the regular PSAT qualifies a student for National Merit.
The PSAT 8/9 is given to 8th and 9th graders in the spring or fall. The PSAT 10 is given to 10th graders in the spring. The regular PSAT is given to 10th and 11th graders only in the fall.
These exams use the same scoring scale. That means an 8th grader who took the PSAT 8/9 and got a 450 in Math would score a 450 in Math on the regular PSAT if she took it the same day. So a student should get better scores on these exams as he or she gets older