I like your eagerness, but I wouldn't recommend doing anything to "get ahead" during the current holidays. You earnt your rest after your VCE exams and, trust me, you'll come to regret it if you stress yourself out too early. Take this time to enrol, pick your units (subjects in uni talk), set up your "adult life" (e.g. get a job, get your Ls/Ps, catch up with your mates), learn the uni lingo, check the
principal dates, set up your timetable on Allocate+ (when available) and join some social events like Orientation (I've heard they're doing a couple of events in January this year).
Generally, textbooks aren't always super necessary, nor relevant to the unit content. Likewise, most students probably won't have access to lectures until much closer to semester (unless they somehow got copies from older students, but that's another story...). You can, however, probably read up on what certain units are like via the
Subject Review thread, if you like, so you can pick the best units for you and your intentions.