It would be a wholesome thing for the DC Circuit to hold DC to "strict scrutiny", but I'm not sure that you are correct regarding the Circuit Court decision. I think the Supreme Court decision was narrower and avoided applying any particular level of scrutiny. I will re-read Heller to see if this is made clear or not.
Somebody else observed (don’t recall where) recently that the bulk of a SCOTUS verdict is basically dicta, explaining why they come to the conclusion they do; interesting as this is, it’s not the absolutely legally binding part. It’s the “Holdings” (or “Held”) part that is the binding core of the verdict, and the pinnacle thereof is the word “affirmed” (or “vacated & remanded”); we can nit-pick the rest, but the final word is in the “holdings”.
Read the footnotes.