Most of Sydneys wind is in the Botany Bay Area. Check out www.nswkba.com.au for a list of maps and descriptions. Make sure you join the club so you can get to know a bunch of great kiters.(PM me if you need some help)The club has a kite buddy system that helps kiters new to the area get to know spots, local rules and other tips.
Some kiters live in San Souci, Dolls Point. Even living in the Eastern Suburbs would be and option maybe 20mins from the closest spot. Northern beaches is mainly surf riding and even tho a beautiful area to live its claimed to get less wind and limited kiting wind directions than the Botany Bay area.
If you want wave action another 20mins from Botany Bay is Wanda Beach. Now its winter there is quite a few westerly's so the Bay area is the only real place in Sydney with spots ridable in a W'ly.
All the best!