The group was formed by entertainment LesPros in 2005 as an idol group of nine members. They received a lot of support from school children from primary school to secondary school. In August 2010, 9nine signed under Sony Music Japan and focus on becoming more of a unity. Besides singing, the group actively participate in the media spotlight as a magazine model, actress.
In January 2007, and Matsuzawa Azusa Miwako Wagatsuma out of 9nine. Shimogaki Madoka and Kawashima Umiker joined as new members.
In December 2007, Kato Rubi has been removed from 9nine that emerged after photographs of her relationship with Takuya Yuya member of HEY! SAY! JUMP.
In March 2009, Marie Ashida Yoshida Mai Yamaoka Midori graduated from 9nine it.
In August 2010, and Shimogaki Madoka Miura Moe graduated from 9nine it.
A new site for the fan club was officially opened in September and announced that he Kanae Murata Yoshii Hirons joined as new members.
• [2007.03.21] first9
• [2008.07.09] second9
• [2006.02.14] Sweet Snow
• [2008.06.24] Show TIME
• [2009.10.21] Smile Again
• [2010.01.20] Hikari no Kage (The Light’s Shadow)
• [2010.12.01] Cross Over
• [2011.03.09] SHINING☆STAR
• [2006.07.26] Shine
• [2006.08.30] Natsu Fuku (Summer Clothes)
• [2007.02.14] Shiroi Hana (White Flower)
• [2008.04.30] SKY (CM Version)
• [2008.06.25] Merry-go-round
• [2009.03.25] Sakura Prelude (Cherry Blossom Prelude)
• [2009.05.20] Unbalance
• [2009.07.29] Happy×2 Eyes