There comes a point when a student actually needs standardized test scores to start thinking about what colleges they will consider applying to.
In my experience, that point comes in 10th grade. A 10th grader who has gotten mostly As doesn’t know, until the first standardized test scores come in, whether he/she has a legitimate chance at highly selective schools or should aim lower.
Fortunately, it is now common for 10th graders to take the PSAT. If the student has already completed geometry (which is on the PSAT), the score obtained in 10th grade can be very helpful. For a student who is still in geometry, the math score may not be so useful because there may be questions on the test that the student can’t answer yet, but the verbal or reading or writing or whatever they’re calling it these days sections are still informative.
I think the OP and the OP’s kid can wait until 10th grade for this information without losing anything important.
As for course placement, the best placement is usually but not always the highest one that works out well for the student. Usually, a kid who can handle honors English should be in honors English, not regular English. There are exceptions. For example, at my son’s high school, honors Spanish was dominated by heritage speakers (kids with some knowledge of the language from outside of school but who were not fluent in it – the fluent kids had a separate class). Kids who were not heritage speakers couldn’t keep up with them, so they ended up in regular Spanish even if they were excellent students of the subject.