I second @ChoatieMom 's sentiment, @bluetoon . My child had to take the placement tests the summer before she began boarding school. She took placement tests for math as well as languages. The math placement put her on a track that was slower than what she had been in public school. At first it seemed a bit alarming, but it soon became a gift. Being on the slower track meant she could spend more time on the material and gain greater mastery. This was evident when she sat for her SATs. She just was more comfortable and familiar with the “tricks” of the test.
As far as languages are concerned, again it might look on paper like she was repeating level 4 of a language. In actuality, the class in BS was far more advanced and nothing like her prior school. She welcomed the learning. The next year, she started in level 5 and migrated to level 6 midway thru the year. So, the school and her teachers supported her when she felt she could progress to a higher level. Also, large® BSs can sometimes offer accelerated classes in languages (as well as math). So, if a student is particularly gifted in a language, they can participate in a class that covers more material more quickly.
In prior posts, @bluetoon, I believe I have suggested that repeating a grade could be a blessing. It is not for everyone. It will cost your parents more money, will take another year to graduate, and there is a greater probability you will contract “senioritis” your last year.
Repeating the 9th or 10th grades is a long standing practice in BS, and I am sure that most AOs would respect a student’s willingness and dedication to prepare for an extra year.