Seven of the victims were related.
The tragedy struck the family while returning home in the car after reaching Thiruvananthapuram in the wee hours by train from Mookambika, a temple town in Karnataka.
They belonged to Bharathannur in Thiruvananthapuram district.
25 people, most of them passengers of the bus, were injured in the mishap and they were admitted to hospital and the condition of two of them was serious.
The bodies of the victims were extricated from the mangled car by police and local people. The deceased included the driver of the car, police said.
Chief Minister Oommen Chandy visited the accident spot and expressed grief over the loss of life caused by the accident.
