Nine is an unreleased instrumental recorded on 1 November 1986 at Sunset Sound in Hollywood, California, while doing post-production on the Madhouse album 8). Although sharing a name and both being attributed to Madhouse, the track is different to the track Nine, released on Madhouse’s second album 16, which was recorded in mid 1987.
Confusingly, the track Six And ½, recorded on 8 October 1986, was originally recorded as Nine, logically following the last recorded Madhouse track before that: Eight. When that track Nine was chosen to serve as b-side for the single 6 it was dubbed Six And ½. With the title now vacant again, Prince at that point recorded this song and titled it Nine
When Prince and Eric Leeds embarked on recording a second Madhouse album in the summer of 1987, this song was not considered, so the first song recorded for the Madhouse album 16 was again named Nine.