Qu. Is it relevant to undertake the bachelor of technology- aviation course to become a fighter pilot in the RAAF which requires a 98 ATAR @NSW ADFA, or are there other paths to that career choice?
There is another path. You can apply through direct entry after Year 12 and still become a fighter pilot (there are people who have done this-
http://forums.whirlpool.net.au/archive/1609608) but be aware that fighter pilot selection is
VERY, VERY COMPETITIVE, so if I were you I would endeavour to earn the highest marks as I possibly could, research my job preference as much as I could (and also other preferences i.e. the role of being a pilot for other planes, just in case-- we have less than 100 F/A-18 Hornets and F/A-18 Super Hornets in the whole RAAF) get as much leadership experience as I possibly could (but don't become one of those sycophantic wankers along the way), get as much flying experience as I could get (if you can afford it but keep in mind that this won't help you in getting your preference as they treat every applicant as an equal no matter how much civilian flying experience one of them have), do as many psychometric tests I could do, and start getting as fit as possible. At the end of the day, though, it's how you perform in your pilot training, once you have been selected to commence training as a pilot, that will determine whether you will be able to become a fighter pilot or a pilot of another aircraft. I recommend you to call DFR and ask them about this and to get your application through as early as possible especially if you are really considering about going to study at ADFA.