All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
The dear questioner may mean the nine books of Hadeeth which are as follows:
1. Saheeh Al-Bukhari, collected by Imaam Al-Bukhari (d. 256 After Hijrah).
2. Saheeh Muslim, collected by Imaam Muslim (d. 261 After Hijrah).
3. Sunan Abu Daawood, collected by Imaam Abu Daawood (d. 275 After Hijrah).
4. Sunan At-Tirmithi, collected by Imaam At-Tirmithi (d. 279 After Hijrah).
5. Sunan An-Nasaa’i, collected by Imaam An-Nasaa’i (d. 303 After Hijrah).
6. Sunan Ibn Musnad Imaam Ahmad, collected by Imaam Ahmad, Maajah, collected by Imaam Ibn Maajah (d. 273 After Hijrah).
7. Musnad Imaam Ahmad, collected by Imaam Ahmad (d. 241 After Hijrah).
8. Muwatta' Imaam Maalik, collected by Imaam Maalik (d. 179 After Hijrah).
9. Sunan Ad-Daarimi, collected by Imaam Ad-Daarimi (d. 255 After Hijrah).
Allaah Knows best.