The OP’s son was 2 points away, but we don’t know if there were 30 other kids who were 1 point away, or who even have interest in honors bio.
When I was in 9th grade, I was put in biology. There were 20 of us at our school (9th grade was still at the jr high) and 20 at the other jr high. No one asked why, no one asked to join the class if they weren’t put in it… That was my assigned science class. Our high school had no AP classes at that time and even today only has 5-6 and it is one of the biggest high schools in the state. There was a perfectly good University down the street and the thought was if you wanted to take a college level class, there were plenty. One guy in my class was not in my special bio class because they’d already moved him as a 8th grader, so he advanced to the high school for science and math and returned to the jr. high for everything else. By senior year in high school, he was taking half his courses at the university. It all seemed so normal to us.