It's ten years in the past, 7 years rule as of now.
7 years limit is a very long period where the student could take up to 4 sittings a year.

What job can someone who has completed the first 9 papers, i.e., left only professional level, get in an audit firm? Internship or associate?

Finish the professional paper first. If you start working you loose your focus.

Audit is good but work like dog. Go after sector like Oil and gas, healthcare, plantation, telecommunication
start from down under.

What job can someone who has completed the first 9 papers, i.e., left only professional level, get in an audit firm? Internship or associate?

Maybe you could try PwC or BDO to be an audit associate, with your completion of 9 papers including your degree in OBU.

It's not easy to work in audit and complete the remaining 4 papers of professional level, better to set aside 1 year to finish up your remaining papers.

Even for the smaller firms, the intensity of work and long OT hours are pretty much the same as well, just be prepared yourselves to cope with the audit peak period and studies at the same time. Just my 2 cents.

Try to finish all the paper. Once you work you got no time for final paper.