Is this situation suitable for high school to study in Australia?

It is not recommended to go out at a young age. I can see that your children like science very much. I think you can find a liberal arts tutor to help him, find someone who comes with him and can control him. For example, math is better than him and English is better than him, but don't put too much pressure on him, so he won't like learning. Personally, I think junior high school children are quite plastic and have their own ideas, but as long as he thinks. This is a question of communication skills.