A learner can pretty much drive what they have access to; dads C63 Merc for example.
But a P plater can only drive P plate approved vehicle (for 1st year or 3 years?).
That means you can do the test in dads C63 but you can’t drive home if you pass
The vehicle you do the test in must meet certain conditions in Victoria, see here. Basically it must be roadworthy and not have a takata alpha airbag As to what is a P plate approved commodore in Victoria, see here. You’ll see VF 6’s are approved 8’s not so much
All this can be found by some google foo or a quick phone call to VicRoads