The Prince George's County yesterday approved the county police union's new contract by a 9-to-1 vote, but only after a last-minute executive session with County Executive Winfield M. Kelly Jr.

Kelly called for the executive session just before 5 p.m. after learning that several council members were upset over not having received the endorsement of a newly formed political committee made up largely of county police officers.

The committee announced yesterday afternoon that it had endorsed only three of the eight council incumbents seeking reelection - Parris N. Glendening, Francis B. Francois and Floyd E. Wilson Jr.

"It's unfortunate that there was some unhappiness among the council members over the police endorsements," Kelly said. "It had drifted up to our office that there was some chance of emotionalism spilling over into the voting and we just wanted to be sure that didn't happen.

"I think the problem stems from the fact that FOP (Fraternal Order of Police) leadership seems to be caught up in getting their games in the paper rather than getting this contract approved.

"We had worked very hard to get to this point and I didn't want emotionalism over a political matter to interfere with what the men on the street having coming to them. We had worked to arrange for the men's retroactive checks to go out tomorrow and we didn't want to have problem with that either."

FOP president Laney Hester, whose group formally endorsed Republican Lawrence J. Hogan in his race against Kelly yesterday, said he saw nothing wrong with the timing of the endorsements.

"I didn't know that you had to time (the announcement of) a decision based on reason," he said. "If members of the council were childish enough to be willing to make a decision on a labor contract over a political issue then I'm very disappointed."

The county and the FOP had agreed to terms July 8 after the police had worked for more than a year without a contract. Negotiations had broken down on June 29 and police staged an eight-day slowdown during which they enforced few traffic laws.

Kelly and Hester exchanged angry words then but yesterday marked the first time since the announcement of the agreement that kelly had criticized the FOP. He had tried to reconcile with Hester during recent weeks in an apparent effort to at least delay the group's endorsement of Hogan.

After meeting with Kelly for about 15 minutes, council members proceeded with almost no debate to approve the contract. Only council member Samuel W. Bogley, who had said earlier he would not support a contract allowing police to retire after 20 years rather than 25 years for fiscal reasons, voted against the contract.