Alexandria school officials last night recommended moving school opening times for junior and senior high school students from the present 9:15 a.m. to as early as 7:30 a.m. and buying additional school buses to transport the students.

John D. Johnson, the Alexandria school transportation adviser, told the school board that changing school hours will be necessary to ease busing problems expected with the opening next year of Metro's Yellow Line to Huntington.

The board agreed to consider a formal proposal in January and initiate public hearings on the proposed change in February.

City secondary-school students currently ride to school on 65 Metro buses that Johnson said are leased at a reduced rate since they are used immediately following the morning rush hour.

But, Johnson said, the opening of the Huntington station is expected to push the area's rush hours later since commuting time will be shortened by the faster subway service.

If schools continue to open at 9:15 a.m., the rate for bus service could rocket from $28 per bus to $160 per bus, Johnson said.

Under Johnson's plan, students at T.C. Williams High School would begin a normal school day at 7:30 a.m. and complete classes at 2 p.m.; students at Hammond Junior High would attend classes from 8 a.m. to 2:30 p.m., and students at George Washington Junior High would be in class from 8:30 a.m. to 3 p.m.

The staggered hours would allow the system to use the same fleet of buses to transport students at all three schools. "It's a big change for Alexandria," Johnson said, "but not an unusual time for opening schools."

Seven to 10 school buses would have to be purchased to replace the leased Metro buses, Johnson said. The system has a fleet of 53 buses that is used to transport elementary school students.

School board Chairman Lou Cook and other members said they are concerned about the effect such school-hour changes could have on the current schedule of early classes, after-school activities and on the schedules of working parents who now can leave for work in the morning with younger children in the care of their older siblings. The normal school day for elementary students begins between 8:15 to 9:15 a.m., depending on the school.

In other action, the board tabled a proposal to make social studies courses mandatory in the eighth grade.