Hm. According to their own website, younger students can no longer take the SAT on a weekend administration date. They may still be allowed to take a school day administration, in October, March or April:
https://collegereadiness.collegeboard.org/sat/register/special-circumstances/younger-students
https://collegereadiness.collegeboard.org/sat/taking-the-test/sat-in-school
https://collegereadiness.collegeboa...st-security-fairness#intended-use-policy

I would imagine that you need to contact local high schools to see if this is an option in your area.

The ACT still allows younger students to test. Pretty much everywhere that you would use the SAT to qualify for access, you should be able to use the ACT as well. There are plenty of resources for familiarizing him with the format, which is not all that different from the SAT. They don't have the Khan Academy partnership, but they do have their own online test review materials:
https://www.act.org/content/act/en/...test-preparation/free-act-test-prep.html

...pronounced like the long vowel and first letter of the alphabet...