Indonesia traditionally has a prisoner remission programme on August 17, the day it celebrates independence from Dutch colonial rule. But cutting the punishment of anyone involved in the Bali bombings will likely anger Australia and other countries whose nationals died in the blasts.
Many of 202 people who died in the bombings were foreign tourists, among them 88 Australians.
The nine prisoners are serving sentences between five and 16 years and were convicted on charges such as robbery to help fund the attack and giving refuge to key figures.
''They are entitled to remissions because they have behaved well,'' Bali's Kerobokan prison chief Ilham Djaya told reporters.
Eight of them are in prison in Bali and one in Jakarta.
Four people serving life sentences for the Bali bombs were not given remissions, he said.
A total of 33 prisoners were jailed over the 2002 Bali blasts.
Among these, Amrozi, Ali Gufron, and Imam Samudra are being held on death row in a jail in Java province for their leading roles in the bombings and are due to be executed this month.
Australia protested against the release in June of Abu Bakar Bashir, a Muslim cleric who served 26 months of a 30-month sentence for conspiracy in the 2002 Bali blasts. The radical cleric's sentence had been cut for Independence Day.