<p>Quote from Marite: "I would not worry about ECs. My S had no sports, no arts. All his ECs, such as they were, were academic, whether they were school-based or not."</p>
<p>I couldn't agree more. Don't define "EC" as something non-academic: if math or any academic area is your son's passion, he should follow that, taking it as far as he can both in and outside of school. For example, in addition to taking advanced courses (check out Stanford's EPGY distance learning program) or working to achieve on competitive math exams/teams etc., he might also be interested in doing a math related research project. That's where some resourcefulness is in order: checking out local universities to get him connected to people in the field(s) he might be interested in who maybe could serve as mentor.
Also, maybe doing a summer internship at a college he's interested in attending (my d. did research at Brown where she later ended up attending). In sum, your job is to just stay with him in terms of finding opportunities he would love that keep him challenged and excited about what he's doing. And believe me, if he follows his passions, schools will not care a whit if he does a sport or anything else. They are looking to build well-rounded classes; they very much like "well-lopsided" kids.</p>
<p>As for those wonderful scores, clearly, he's done with SAT I's. The SAT II"s should be taken as soon as the relevant course work has been completed, eg. my son took the Math SAT II after 8th grade because that's when he finished BC calc. The only headache was that by the time he was applying to college, that score had been "archived", so I had to call and have a special separate "archived" score report sent (but schools will see the dates and that will really make your son stand out from others will similar scores).</p>
<p>Anyway, best of luck, and enjoy the ride!</p>