Who was the young prophet in 2 Kings 9? He is variously called the son of a prophet, the servant of a prophet, and a member of the prophets guild. Jehu and King Joram's other generals knew him by sight, but he is never named in the text.
When he delivered the message to Jehu, he went far beyond the words that Elisha told him to speak. A prophet might deliver messages for other men, but ultimately he delivers messages from God. Nobody has the authority to dictate prophecy to a prophet except YHWH. Were the extra words given to him by God at that moment? Maybe. The absence of a name really makes me wonder.