Prince George's County will use approximately $9 million of additional funding scraped together during this year's session of the General Assembly to avert all but about a dozen of 412 planned county worker layoffs, government officials said yesterday.

"It's going to be tight," said County Executive Parris Glendening, "We're going to have to squeeze every penny, but I think we'll make it."

Glendening said that even with financial help from Annapolis, he will not have enough money to restore 150 slots for classroom teachers, which were eliminated in last year's budget, and will not fill approximately 150 other county jobs that are expected to become available over the next budget year.

Those positions include about 36 police officers who will not be replaced, eventually reducing the number of sworn officers next year from 944 to 872.

In his budget message to the County Council delivered on March 31, Glendening included a list of $23 million worth of jobs and county services--in order of priority--that should be restored if financial aid was obtained in Annapolis.

On April 25 he will submit a "supplementary letter" to the council adding $6 million to $8 million in revenues that Prince George's expects to get from the new Maryland Lotto game approved by the legislature last week; $1.5 million in additional state education aid and $700,000 in additional state funding to support emergency "911" telephone service. The total county budget for fiscal year 1984, which begins on July 1, is $528 million.

In addition to saving jobs, the restoration of $9 million on Glendening's $23 million list will also cover the purchase of 19 badly needed dump trucks and front end loaders for the Department of Public Works and 100 new police cars. The money will run out, however, before the county can replace 15 pre-1978 ambulances run by the county fire and rescue service.

With the extra money, Glendending also will keep 45 teachers, 36 policemen, 25 firefighters, 60 elementary school health aides, 57 elementary librarians and approximately 189 other county employes who were expected to be part of the layoffs. Nearly 40 percent of the addbacks would go to the Board of Education.

Other items that will not be restored because they were low on the priority list include $300,000 for classroom books and supplies, funding for 33 vacancies in the public works department, $1 million for school maintainance and repair, an additional mobile intensive care unit for the rural south county area and money for 25 additional police and 10 additional firemen.

Glendening acknowledged, however, that the County Council will have the final say over how the scarce additional funds will be used and may have some different priorities.

"We have to start providing basic services again, we just can't do everything we used to," said council member James Herl of College Park. Herl specifically criticized spending nearly $1 millon for the new police cars when vacant positions will not be filled.

"What good are the cars if you don't have the police to put in them?" Herl asked.