Ninth Doctor audio stories

The Ninth Doctor has featured in several audio stories

Audio companions of the Ninth Doctor

 * Rose Tyler (Destiny of the Doctor, The Ninth Doctor Chronicles)
 * Adam Mitchell (The Ninth Doctor Chronicles)
 * Jack Harkness (Destiny of the Doctor)

New Series Adventures
After the Twelfth Doctor was hit by energy from the time storm, he entered a degeneration cycle, going back from his eleventh incarnation to his first.