Our school doesn’t allow freshmen to take any APs. The IB curriculum starts in 10th grade and takes up the entire schedule for 3 years, with one slot for an elective in 11th grade.
Many APs at our school such as Gov and Econ aren’t available to IB students because they are restricted to 12th grade (when IB students don’t have an elective slot). All IB students are required to take special gov and econ classes that are part of the IB curriculum, but are not considered honors.
My kid was able to take 5 APs in addition to the full IB Diploma. Our school allowed for AP classes in 9th and 10th grades, so they took 3 APs in 9th grade (US Gov, Human Geo, and Stats), US Hist in 10th, and CalcBC in 12th. Also, they were able to sit for two SL exams in 11th grade (Spanish & Math) thereby leaving one SL (Design Tech) and three HLs (English, Asian History, and Physics) for 12th grade IB tests. Our high school offered engineering classes as electives, so that’s what my kid took for electives each year, as well as drawing&painting in 12th.
Also at our high school, a student was only allowed to take IB classes if they were an IB Diploma candidate. That was the spoken rule, but I think there were exceptions made from time to time. The school counselor would check the “most rigorous” box on the form submitted to colleges only if that student was in the IB Diploma program. Again that was the spoken rule but I suspect there were exceptions to that as well from time to time.
There seems to be quite a bit of interpretation from school to school about what classes are allowed in what grade. I don’t understand the restrictions against AP classes in 9th grade, unless it’s a crowded school and the school wants to leave space in the AP classes for upperclassmen.