Not exactly true. Despite not being vaccinated, he was granted an exemption for having proven a recent COVID infection in December. The state government of Victoria and Tennis Austrailia, the organization behind the tournament, granted him the exemption. However, his team did not apply for one from the federal government and the federal government had not granted him one before arriving.

Edit: Just found out from another reply to one of my comments that he likely also falsified his PCR report :\