Six others were handed 10 years in jail on Thursday each for their role in the unrest, General Prosecutor Ahmed al-Hammadi said.
The nine were tried for attempted murder of police officers, possessing explosives and participating in clashes in March 2014, Hammadi said, AFP reported.
Bahrain last month sentenced eight people to life in jail allegedly for "terrorism" and violence against security forces in January last year.
The tiny Persian Gulf state has been shaken by unrest since it quelled a popular uprising demanding reforms in 2011.
The kingdom, connected to Saudi Arabia by a causeway, lies across the Persian Gulf from Iran and is home to the US Fifth Fleet.
Despite the crackdown on the 2011 uprising, protesters frequently clash with police in Shiite villages outside the capital Manama.Tasnim News Agency - world