Thirty people were also injured when the bus carrying 50 passengers veered off a road and fell some 60 feet down the road in Sidhuwa area.
Former Minister of State for Finance and Maoist leader Hari Raj Khewa was among the nine people died in the accident, police said.
Khewa was the chairman of CPN-Maoist Centre Dhankuta District Committee.
The injured have been admitted to a local hospital for treatment.