A nine-man regency council was established today, paving the way for the departure of Shah Mohammad Reza Pahlavi on a foreign vacation and possibly permanent exile.

But even before the announcement of the formation of a regency council to preserve the monarchy's outward form during the shah's outward form during the shah's absence, Ayatollah Ruhollah Khomeini, the chief opposition figure, raised the ante and further complicated the effort to avoid a potential political vacuum facing Iran.

In a move clearly challenging the monarchy itself, the Paris-based Moslem leader announced creation of a Provisional Islamic Revolutionary Council as a first step of a process to turn Iran into an Islamic republic.

Combined with his call for strikes, demonstrations and boycotts against Prime Minister Shahpour Bakhtiar's shaky government, the move by the 78-year-old exiled religious leader threatened to split the opposition, united solely in the desire to overthrow the shah.

With Bakhtiar's government nearing a vote on parliamentary approval, after which the shah has said he would leave, Khomeini's timing caught some of his key domestic supporters by surprise.

Spokesmen for National Front opposition leader Karim Sanjabi, who told a packed anti-shah rally at reopened Tehran University, "I hope we see him [Khomeini] very soon," later said they had not been informed about the Islamic Council announcement, which was read at the meeting.

The National Front spokesmen showed irritation at Khomeini's go-it-alone tactics.

Iran now appears to be grappling with a situation that includes an ever-weakening shah, a still unsteady appointed government, a rival, but foreign-based political challenge, a potential coup d'etat and threat to opposition unity.

As impressive as was the peaceful demonstration by perhaps 100,000 Iranians today -- a smaller version of last month's anti-shah marches though the capital -- observers were struck by burgeoning differences in opinion now that the opposition's single-minded devotion to the shah's down-fall seems about to pay off.

Random interviews with three American-educated Iranian professors at the anti-shah rally at the university revealed no agreement about the Bakhtiar government.

One predicted that Khomeini would return and sweep the Bakhtiar Cabinet into the dustbin of history within two days. Another gave Bakhtiar two weeks while the third hoped Bakhtiar would remain in office for three of four months to "help coll things down."

Left unsaid was growing concern about Khomeini, whose supporters are beginning to realize that he is an old man likely to be out of touch with contemporary Iran's problems after his 15-year exile.

Moreover, if Khomeini does return soon, many thoughtfull Iranians are convinced the restive armed forces will seize on his presence to stage a bloody coup d'etat.

Despite the demonstrations, more motorists ventured forth today than in the past two weeks. More stores were open. Th central bank even cleared checks. The atmosphere suggested that Iranians may have already written off the shah and want to get back to work and normality.

Despite their outward support for Khomeini, local religious leaders and hard-hit merchants are reported considering sending delegations to France in hopes of convincing him that accepting the Bakhtiar government is the best way to save Iran from chaos.

So far little in Khomeini's past behavior suggests he would accept such a solution, which would strengthen Bakhtiar's hand and doubtless bring him considerable popular support if elections are held in June, as required by the present constitution.

By the same token, Khomeini may fear being cheated of his goal of establishing an Islamic republic if he were to tolerate Bakhtiar, who is on record as favoring the monarchy's preservation.

The makeup of the regency council did little to encourage opposition support since no bona fide religious leaders or major lay opposition figures were included in its ranks.

The members, according to Pars, the national news agency, are: Bakhtiar; court minister Ali Qoli Ardalan: Lt. Gen. Abbas Garebaghi the recently appointed senior military official; the National Iranina Oil Co. chairman, Abdollah Entezam; Judge Addol Hossein Aliabadi; former minister Sayed Jalaleddin Tehrani, once an Islamic mullah; former minister Mohammed Ali Varesteh, and the speakers of the lower and upper houses of parliament, Javad Saeed and Mohammed Sajjadi.

By contrast, Khomeini appeared to be setting up a kind of rival political system, almost a parallel government.

Meanwhile, Ardeshir Zahedi left for Switzerland today on his way back to Washington, where he is expected to relinquish his post as ambassador to the United States.

Zahedi, who for the past six weeks has tried to rally hard-line military support for keeping the shah on his throne, was expected to make plans for welcoming the monarch in the United States, where he is thought likely to spend mos of his vaction.

Oil production meanwhile, rose to 480,000 barrels a day, twice as much as last week, but still half the normal domestic winter requirements. One Tehran refinery was reported working at half capacity while the refinery in Tabriz was said to be producing at 70 percent normal capacity.