It's pretty plain, your 90 day report is due on the 9th May. As it is your first report it will have to be done in person and you can lodge your application for residence certificate at the same time. It usually takes about a week.
The O-A multi-entry from Australia does not require you to have any money in a Thai bank account, only sufficient funds in Australia to meet the requirements. If you use the multi-entry wisely you can get 2 years from that visa. I would suggest that you look at the O-X from the Thai Consulate in Sydney, not Canberra, far better visa for long term.