The Public Health Orders are quite clear:
1. If you are not fully vaccinated you cannot meet in groups and play tennis
You can play with one other person or persons of your household
2. If you are vaccinated you must be able to produce evidence, either digital or paper certificate, to the leader of the group.
TennisNSW has released their playing policy as of 8/10/2021. This link connects to their latest policy on their website.
https://www.tennis.com.au/nsw/news/2021/10/08/covid-19-update-as-at-8-october-2