[CTcard]

Second of all, am I reading correctly that Booker took and got A's in two Stanford classes when he was 16? Impressive.

That would presumably be most likely something along the lines of the Stanford Pre-collegiate Summer Institute, where they offer courses for high school students.
https://summerinstitutes.stanford.edu/

In general, one cannot take regular Stanford courses without being an enrolled (and thus accepted) Stanford student.

[CTcard]

Second of all, am I reading correctly that Booker took and got A's in two Stanford classes when he was 16? Impressive.

That would presumably be most likely something along the lines of the Stanford Pre-collegiate Summer Institute, where they offer courses for high school students.
https://summerinstitutes.stanford.edu/

In general, one cannot take regular Stanford courses without being an enrolled (and thus accepted) Stanford student.