For accommodation i'd recommend speaking with the kite school you'll be working for and see if they can line up something like a share house or put you in touch with some of the other instructors.
For the wetsuit / boardshorts thing... the style around these parts are to wear a wetsuit with boardies over the top.

The water temperature at the moment is ~18ºc but over summer it'll get up to about 22-23º. Most people are wearing wetsuits at the moment (myself included). That said coming from the EU you'll probably be fine in nothing more than a mankini or budgie smugglers.

(Please don't wear a mankini or budgie smugglers... they're not typically Australian and we'd rather not cop an eyeful of baywatch buldge).