Salah bin Abi Maryam صالح بن أبي مريم الضبعي - أبو الخليل · The Promised Deliverer (Kitab Al-Mahdi)

The Prophet (ﷺ) said: The Mahdi will be of my stock, and will have a broad forehead a prominent nose. He will fill the earth will equity and justice as it was filled with oppression and tyranny, and he will rule for seven years.

The other narrators mentioned "nine years" from Hisham except Mu'adh.