No, this bill specifically only makes it possible to penalise the platforms. Parents or children cannot be penalised. The precise wording in the bill is:
A provider of an age-restricted social media platform must take reasonable steps to prevent age-restricted users having accounts with the age-restricted social media platform.
Civil penalty: 30,000 penalty units
There are also penalties that can apply to individuals, but only if:
the person is a provider of an age-restricted social media platform;
or
the person is a provider of an electronic service;
(To the penalty of “Civil penalty: 500 penalty units”.)