The chapter "Talent Searches and Accelerated
Programming for Gifted Students" in volume 2 of A Nation Deceived http://www.accelerationinstitute.org/Nation_Deceived/ND_v2.pdf
makes recommendations (quoted below) on acceleration and enrichment based on talent search SAT or ACT scores. If your son scores high enough he should at least consider grade acceleration or early college.

PROGRAM RECOMMENDATION BASED ON SAT I OR ACT PERFORMANCE RANGES
TABLE 4.
A Range
230–470 on SAT-V
200–510 on SAT-M
OR
0–21 on ACT-Eng or ACT-Read
0–17 on ACT-Math
Program options should include:
1. Long-range academic planning, following
Sequence 1 in area of academic strength
2. Early access to advanced school courses
3. Supplement coursework with
enrichment-oriented school, Saturday, or
summer programs
4. Early career counseling
5. Sequence 1 of “Recommended Course
Sequences”

B Range
480–580 on SAT-V
520–600 on SAT-M
OR
22–27 on ACT-Eng or ACT-Read
18–23 on ACT-Math
Program options should include:
1. Long-range academic planning, following
Sequence 2 of “Recommended Course
Sequences” in area of academic strength
2. Fast-paced school, Saturday, or summer
classes in area of strength, using
“curriculum compacting” to compress
courses into shorter time frames.
3. Early access to college-level coursework
through Advanced Placement (AP),
distance-learning, dual-enrollment, or
summer courses.
4. Early career counseling, including access
to mentorships, tutorials, and internships.

C Range
580+ on SAT-V
600+ on SAT-M
OR
28+ on ACT-Eng or ACT-Read
24+ on ACT-Math
Program options should include:
Options 1–4 from B Range, plus:
5. Individualized program of study, using
“test-out” approach in areas of strength.
This helps advanced students avoid
spending time on material they already
know.
6. Consider grade acceleration (grade
skipping) or early admission to college
7. Individualized work with a mentor
to pursue advanced study in an area,
possibly aimed at a specific AP exam.