The Boy Who Went Boom by Michael Wardner

Ultra was the world's greatest superhero. A boy named Daniel Cotton just killed him. The fight against evil was never-ending—until now. A post-apocalyptic, super-villain coming-of-age tale. A fast-paced thriller set in a future ruled by superheroes. One young boy has the power to change the world --if only he could control it. Until then, there’s only one thing Daniel can do: run.