The USCG NMC is a very screwed up and understaffed operation. I find it hard to believe they would try to look for anything without being prompted to do so. If your doctor and records are gone, there is nothing for them to find.
A 9 year old child cannot be expected to understand or remember his diagnosis or treatment 20 years ago. Now 20 years later, you don’t know what your diagnosis was, what your treatment was, or what the result was, except you are here today. You don’t know whether the doctor was a pill-pushing quack who didn’t know what he was doing. Apparently your parents thought so. You may think you know, but you don’t. You were a child. It was a long time ago. Your mind is playing tricks on you, you think you now know something from your childhood 20 years ago, but you don’t know.
What we know today is that ADD is a poorly understood and grossly overdiagnosed malady. We know today that Ritalin was, and is, grossly over prescribed.
Your childhood memories of a possible diagnosis and treatment for which there are no records, and that you may, or may not , have had 20 years ago is unrealiable. You don’t know. Don’t speculate. Don’t say anything.