Two cars and a lorry were involved in the collision which happened at about 12:15 at Ralia south of Newtonmore.
The Scottish Fire and Rescue Service helped to free people from the wreckage and those hurt were believed to have serious injuries.
One of those injured in the accident, which involved an Astra, a Volvo and an HGV, was flown to hospital by an air ambulance.
The road at the scene was closed for several hours and traffic was diverted via Newtonmore before the A9 was fully reopened.
Following a collision between a car and a recovery vehicle, six people have been injured.
At approximately 6.30 p.m. on Thursday, emergency services were called to the scene of an automobile and recovery vehicle collision at the Glentruim intersection of the road between Ralia and Dalwhinnie.
The male driver of the vehicle, 52, was detained and charged in connection with the incident, according to Police Scotland. He is scheduled to appear in court at a later time.
Due to traffic violations, the recovery vehicle’s 44-year-old male driver was also taken into custody.
Around 10.15 p.m., the road was completely reopened after being closed to facilitate recovery.
Much further north, on the same road, there was another crash that sent a motorcyclist to the hospital.
There was only one car involved in the collision, which occurred at the Berriedale Braes at approximately 11:40 p.m.
