Nine persons were taken to hospitals here last night after their National Airlines jetliner, flying to New York from Miami, encountered turbulence on the way, and was diverted to National Airport.

None of the injuries appeared to be serious and by late night, most of the nine had been released or were expected to be released shortly.

The Boeing 727 jetliner, carrying 85 passengers and seven crew members, was about 50 miles south of Richmond, flying at 33,000 feet when it encountered what its captain described as moderate air tuburlence, according to the Federal Aviation Administration.

After the plane landed here at 7:35 p.m., FAA, Alexandria and Arlington County ambulances took one person to Alexandria Hospital, two to Arlington Hospital and six to the National Orthopaedic and Rehabilitatin Hospital in Arlington.

Injuries reported included pains in the shoulder, back, chest, leg and neck. A small boy suffered a bruise on his head.

Passengers appeared "more shaken up" than seriously injured, said one medical worker.

The FAA said no structural damage to the plane was found. It left here for LaGuardia Airport at 9:14 p.m.

The plane, which left Miami at 5:25 p.m., encountered the turbulence about 1 1/2 hours later. Clear-air turbulence, an atmospheric disturbance that occurs in cloudless skies at altitudes between 4 miles and 7 miles, can be violent and hazardous to aircraft.