Yes HtDP was designed to be more approachable for a wider audience and doesn't require familiarity with undergraduate freshman math, physics, and electrical engineering. It could be used as an introduction to programming and CS for anyone who's taken middle school algrebra.
For high school students, it's likely to be more appropriate.
That said, if a student expresses an interest in SICP, they shouldn't be dissuaded from tackling it.
They overlap some, but also each have unique lessons from a student would benefit.
HtDP is all about a 'design recipe' which is worth understanding even if you've studied SICP. On the other hand it's very slow-paced in comparison and won't stretch you the same way.
