<p>So much depends on your state. Are you in NY, as some of the others are thinking?
Unless your kid is also a math genious, don’t go more than a year or two above the normal science sequence for 9th grade. He can probably handle 9th grade bio as a 7th grader but it gets harder - my D had AP Physics concurently with pre-cal as a 10th grader. Hard slogging!
Playing devil’s advocate in my field - our country needs good earth scientists! Don’t write it all off as “science lite”, although that’s what usually happens. IF your kid will be a humainities major, this may be the only science class they have to be their base for later political decisions re global warming, etc. They need good tools for forming opinions.</p>