Hey Foosh,
This is a champion time of year, the sun is out, it's warm, the water is still warm at 20 degrees. There's some swell about, but realistically you need a boat to access places like little island, Alkimos, Rotto etc unless you want to surf with 40 or 50 of your mates

The water is beautiful for diving at the moment all you need is a decent wetty. An open cell inner 3mm freedive suit is more than adequate at the moment and a 5mm kills in even late winter down on the south coast.
Still plenty of good fish running ATM.
Embrace Autumn, you just need to tool/toy up for the conditions. Freedive spearfishing on windless sunny days when it is a glass off is pure heaven.

Just pack the kites away until winter, dust off the surfboards or start landboarding with a kite, there's some fun!
Good winds,