There are nine planets according to Jyothisham they are Ravi (Sun) Chandra (Moon)
Kuja( ),Budha ( ),Guru ( ), Shukra ( ), Shani (Saturn),
Rahu, Ketu. These Nine Planets moves around the 12 raasis or birth sign, passing through 9 paadas of stars or nakshatras in each raasi. All the 12 lagnas or raasis rotate during the day. While the person takes birth on certain time, his or her future depends upon the grahas position at the time of the birth.
So the Nava Grahas or Nine planets shows a very important role in the persons career.