The victim was identified as Yusuf Ali, 45, who was working as the assistant to the driver of the accident-ridden Taj Paribahan bus.
The incident occured on the Dhaka-Thakurgaon Highway near Jagannath Union's B Akhra Government Primary School around 4.45 am on Saturday, said Thakurgaon Sadar Police Sub-Inspector Ahmadullah Hoque Prodhan.
The bus was heading to Thakurgaon from Dhaka at night when the vehicle veered out of control and crashed into a tree, said SI Ahmadullah, citing eyewitnesses.
They were rushed to Thakurgaon Sadar Hospital where Yusuf died during treatment.
Prabash Kumar Rai, the hospital's caretaker, confirmed Yusuf's death and said one of the nine victims had been sent to Rangpur Medical College Hospital after her condition deteriorated. The others remain in treatment at Thakurgaon.