Unfortunately, a WCC is actually a legal requirement to tutor.
That being said most individuals who tutor do not have one, as most of them are Year 12's who have recently graduated and are unaware of the legal requirements. I am unsure what you mean when you say "legit", but if you are referring to the professionalism behind it, most tutors should be professional, but I have seen tutors that unprofessional in the way they teach, i.e bad tutors.
As a general rule, most tutors start off with a trial session if you are interested.
If you are afraid of getting a "bad" tutor, then start with a trial session at the library that is not too close to where you live. If you feel that they are unprofessional, then the next time you get a text from them just reply that you have found another tutor. That way, you don't have to invite them into your house
In regards to the qualifications, you should be able to identify the from the list in the high achievers list. Most tutors will be the high achievers, and you can find them by googling 20xx VCE high achievers, where the 20xx is the year they graduated. You should be able to find them on the site
If not, you can ask them what they got in VCE, as well as ask for them to show you the relevant documents.
If, you don't want to go through the hassle of doing that, then Connect Education has already done that, all the individuals below are lecturers that are great tutors. You can find them in the list below
https://www.connecteducation.com.au/resources/vce-tutoring