My son was similar to this.At 9 years he had a bone age of  15. He was, however, only the height of an average 9 year old. After a lot of questioning (even threatening to bring him to another specialist in another country) he was admitted for a series of tests. As a result he was put on daily injections of growth hormone. Sometimes I wonder if they were really necessary.His bone age went to 16 and remained there, while he continued to grow. When he was 17 years growth stopped, he is 65 inches tall. When he was 9 I was in despair about his adult height. His paed. said, at the time, that he had about 2 years growth.Thankfully he was wrong.He is SWCAH.