Hi Ben, 

I've reviewed your request regarding deleting SAT scanned tests and it appears that this is something that should be handled directly by College Board, and not under Khan Academy purview.

For that reason, I encourage you to reach out to the College Board Support Team. You can contact the College Board Support here.

Also, you should know that the Test Prep is based on either your scanned scores or by taking a full Practice Test. This will be diagnostic to what you need to practice for the SAT. 

Kind regards.