It has always been very individual. The age/birthday of the student. Are they advanced academically or do they have so me challenges. Are they small for their age. Are they going to play a sport and some maturity would be va,unable. We asked admissions at two schools about the their thoughts re repeating or not. We were told what I just relayed. Further, about 25% of students repeat. Not just 9th grade but for all grades.