You know your DS better than any neuropsychologist on Earth. You are the world's leading expert on your DS! Don't ever discount your own expertise and what your gut tells you. The times that I have overruled my intuition and proceeded against it have been my biggest parenting mistakes. My DS is ADHD and you describe classic ADHD behavior in your post, silliness and impulsivity, emotional reactivity, needing repeated prompting, not just at school but at home too.
I have come to realize in parenting an ADHD kid that lack of impulse control is really the gravamen of ADHD although the focus of treatment is on attentional struggles. It's the impulse control issues that disrupt attention. Let me tell you from where I sit with DS16 that he began to have significant social struggles at school around the age of your son. Other kids don't like a disruptive kid who blurts things out all day every day in class. My DS is by temperament a very sweet, loving kid, lacking any of the aggressive issues that can occur with ADHD. However, his complete lack of impulse control coupled with the inability to read social cues and situations (ADHD kids are 2-3 years behind neurotypical kids in social maturity generally) made him a virtual outcast at school around 5th grade when the other kids started maturing socially. And he was medicated for ADHD and in therapy for it as well at that time.
So, all of this to say, trust your instincts. RUN, don't walk to have ADHD thoroughly assessed and controlled, if needed, to support your DS academically and socially. Good luck!
