I'm just gonna suggest having your cat as an inside only cat, except when out in an outdoor run or in the yard on a harness.
Cats are so damaging to the native environment, especially animals. They are not native in Australia, so our native prey animals haven't yet evolved to be able to protect or defend themselves from cats.
As well as that it's dangerous for the cat. They can easily be poisoned or killed by someone who hates cats (I've met people that kill cats for fun, and it's legal because they can just say they thought it was a feral). A lot of people hate cats. I had an outdoor one once that came home, and the vet and us think it was most likely somebody kicked the poop out of her

. They can be hit by cars, get in fights with other animals, killed by dogs, get lost.
Much safer for the cat and wild animals to keep the cat inside IMO.
As for scratching, get a few scratching posts, lots of toys, and spend lots of time playing with your cat and keeping it from getting bored. Get some toys it can play with by itself and rotate them as well