The group later forced their way onto the site by moving a fence and entering the former camp without authorisation, police said.
Officers were called to the scene and detained the men, who were taken to a police station in the nearby town of Oświęcim, Polish state news agency PAP reported.
"Based on the evidence gathered, the detainees were charged with unlawful entry onto the grounds of the former German Nazi concentration camp," regional police said in a statement.
The nine suspects admitted to the offence and agreed to a penalty. In coordination with prosecutors, each was fined PLN 3,000 (around USD 850) and ordered to pay an additional PLN 1,000 to the Auschwitz-Birkenau Memorial and Museum, according to the statement.
Nearly 2 million people from around the world visited the site in southern Poland last year, with Poles accounting for about a quarter of that number, according to the museum.
The largest numbers of foreign visitors came from Britain, Italy, Spain, Germany, the United States, the Czech Republic, Israel and the Netherlands.
More than 1.1 million people—mostly Jews, along with non-Jewish Poles, Roma and Sinti, Soviet prisoners of war and people of other nationalities—were murdered at Auschwitz during World War II.