Six current and three former FC Thun soccer players accused of having sexual relations with a minor.
Five other individuals, who are not soccer players, also have been accused, the office of the investigating magistrate of the Bernese Alps said.
Most of the suspects acknowledged they had sexual relations with the girl, the magistrate's office said.
The accusations opened a formal case against the individuals, after police of canton (state) Bern last week temporarily arrested a dozen FC Thun players and others on suspicion of having sex with a 15-year-old girl.
Under Swiss law, the action formally opened criminal proceedings against the suspects. Should the prosecutor then conclude there is sufficient evidence, formal charges could be brought.
Authorities identified none of the men by name, in line with Swiss privacy laws. FC Thun said it was unable to name the suspects because it was not party to the criminal proceedings and had no access to the file.
The girl, who has since turned 16, is receiving counseling.
It is illegal under Swiss law to have sex with a minor under 16 if the age difference is greater than three years. Police did not release the ages of any of the men they arrested. The maximum penalty for sex with a minor is five years in prison.
FC Thun president Kurt Weder has said he was shocked and dismayed by the arrests. If charges were brought against the players, they would immediately be suspended from training and matches, he told Swiss radio DRS.
Thun stunned Europe in 2005 by qualifying for the group stage of the Champions League. With an annual budget smaller than the individual salaries of many top players, Thun was the smallest team to ever advance to that stage.