A federal judge in Missouri ordered the Education Department last week to stop using public money to provide remedial instruction to children in religious schools, in light of the Supreme Court's decision last month that such programs violate the constitutional doctrine of separation of church and state.

In Kentucky, another group of plaintiffs is citing the Supreme Court decision and asking a federal judge there to impose a nationwide injunction, barring the use of Title I money in religious schools.

With schoolhouse doors set to open in a few weeks, these court cases and others have thrown the Title I program, under which federal money is provided to local school districts for disadvantaged students, into chaos. State and local education officials are awaiting some Education Department guidance on how to continue the program for children in schools affiliated with religious groups without violating the high court's decision.

Secretary William J. Bennett is drawing up his own plan to distribute Title I money via a voucher system to parents, who could redeem it at the school of their choice. But Congress does not return until September and is unlikely to approve a voucher plan very quickly, leaving the entire question unsettled for the coming school year.

Bennett, appearing Sunday on NBC's "Meet the Press," suggested another alternative: religious school students who receive Title I remedial courses may have to move to a neutral site, such as a trailer behind the school, for the instruction.

All the department will say is that it is reviewing the Missouri case in light of the Supreme Court decision. "The department will probably be issuing some guidelines," said spokesman Marie Robinson. "The schools want to know what to do and what they should be doing."

Robinson did say that later this week department lawyers will file a response in the Kentucky case.

EDUCATION EXPERTS . . . The July edition of The Executive Educator, a private magazine, carries a guest column titled "Here's What Education Needs" by none other than Ronald Reagan. In listing what he sees as the five key aspects of American education, Reagan mentions the importance of parents and quotes "a widely respected educator, Dr. Eileen Gardner."

Education watchers will recall that Gardner was Bennett's special assistant for educational philosophy, who was abruptly dismissed after her controversial views on educating handicapped people ignited a firestorm of criticism. Gardner had written in a report for the Heritage Foundation that handicapped people had "summoned" their disabilities and created a powerful "iron triangle" lobby in Washington, with congressmen and bureaucrats, to protect their special programs.

"The success of the handicapped constituency at the federal level was impressive," Gardner wrote for the foundation. "It had money, 'deep conviction,' and little opposition. It seemed to occupy the moral high ground, which few could bring themselves to oppose." She said the handicapped have pushed "increasingly unreasonable demands," while they have "selfishly drained resources from the normal school population."

The Gardner quote that the Reagan article cited was: "The record shows that when control of education is placed in federal hands it is not control by the people, but by small yet powerful lobbies motivated by self-interest or dogma. When centralized in this way, it is beyond the control of the parents and local communities it is designed to serve. It's become impervious to feedback."

BILINGUAL BROUHAHA . . . The outcry continued this month over Bennett's decision to appoint at least three outspoken critics of bilingual education to the government's main bilingual advisory panel. Before Congress left town for its August recess, Rep. Henry B. Gonzalez (D-Tex.) introduced a strongly worded resolution expressing Congress' disapproval of the appointment of Anthony Torres, Robert Rossier and Howard Hurwitz to the National Advisory and Coordinating Council on Bilingual Education.

The Gonzalez resolution, which now has about 15 cosponsors, says the appointment of the three "severely limits the council's ability to provide objective and reasoned advice."

Gonzalez got some assistance from the head of the Congressional Black Caucus, Rep. Mickey Leland (D-Tex.), who took to the floor to decry how "the Reagan administration has again shown its insensitivity to the concerns of the minority communities of this country."

Leland directed his fire specifically at Rossier, who wrote an article for the Washington Times calling bilingual education "The New Latin Hustle" perpetuated by "power-seeking politicians." Leland called Rossier's appointment "disgraceful."