He lived in Indonesia (with his muslim step-father) from age 5 to 10. Indonesia is fairly close to Australia.
There was documentation posted here perhaps within the past year suggesting he had travelled on his mothers passport until age 9 or 10. The document(s) demonstrated she applied for a passport that did not list him. Might have been associated with her shipping him back to HI. Someone who keeps better track of these things will know.
If he did not have his own passport at age 8, then he likely travelled to Australia with her.