They were attempting to get better seats at the Australia v Serbia men's basketball semi-final at the Rio Olympics without proper accreditation.
The athletes were questioned by police on Friday and released on Saturday.
Australia's chef de mission Kitty Chiller said her country's Olympians were "definitely not at fault".
Cyclists Ashlee Ankudinoff and Melissa Hoskins, rugby sevens player Ed Jenkins, archers Alec Potts and Ryan Tyack, rowers Olympia Aldersey, Fiona Albert and Lucy Stephan and hockey player Simon Orchard were the nine involved.
Fiona de Jong, chief executive of the Australian Olympic Committee (AOC), said the athletes entered the arena by "mistake" and that "no-one was arrested".
The AOC is "making steps" towards paying the 10,000 reis (£2,386) fine per athlete.
"Every jurisdiction has their own local laws, and we are in Brazil so we understand that our athletes need to adhere to the Brazilian law," said de Jong, adding the athletes had been dealt with "fairly".
Chef de mission Chiller said an internal investigation was taking place, but that the process of putting a sticker on your accreditation with another venue access code on it is "traditional" at Olympic Games.
She said she was "disappointed" at the athletes' treatment, adding: "We have and will continue to provide as much support and counselling to them and their parents."
The latest incident comes after Australian swimmers Emma McKeon and Josh Palmer were issued with a curfew after staying out late drinking on Tuesday.
McKeon will now be allowed to attend the Olympic closing ceremony on Sunday after appealing successfully against the decision to ban her.
Nine Australian Olympians have been fined for falsifying documents, an offence that can carry a prison sentence of up to five years in Brazil.