On 15 September,
Core Contents Media revealed that T-ara will make their comeback on 10 October 2013. The song was said to have a "stronger sound", but still remain catchy. On 26 September 2013, T-ara released a 30 second teaser video, filmed in a desert. On 1 October, T-ara released another teaser for "Number Nine" on their official website. In their black-and-white teaser, they used an "upgraded mature beauty". "Number 9" is an electro-pop dance song with sad lyrics and melody. It was choreographed by Yama & Hotchicks, who also choreographed "
Bo Peep Bo Peep".The song features a gentle guitar melody, coupled with an "unexpected intense sound". It was co-composed by Sinsadong Tiger and Choi Gyu Sung. "T-ara Party Non-Stop Remix" by DJ Takao Fukushima is composed of ten songs spanning 45 minutes: "Bo Peep Bo Peep", "Yayaya", "
Lovey-Dovey", "
Roly-Poly", "Waeroni", "Bye Bye", "Like The First Time", "
Target", "
Bunny Style!" and "Deja-Vu". The single was released in four different types: two CD+DVD limited editions that come in a special paper jacket, a regular edition, and a X-mas edition that comes with a remix album and a DVD, packaged in a box with six "T-ara Santa Ver." rubber key holders. All editions of the single come with a trading card with a serial code, chosen randomly out of seven types. == Promotions ==