G'day,
yeah the best place is at a creek mouth but your unlikely to go there this time of year as the trade winds won't be the right direction til probably October at the earliest if we're lucky.
We won't have any worries about stingers this time of year either and personally I've never seen any crocs where we kite (this time of year) so its no big deal, I've been kiting since 2003 and windsurfed for years before so its fairly safe.
Your more likely to die of liver failure with the amount of beer you end up drinking!
cheers,
Robbie

p.s. here's a stinger video
p.p.s.
http://www.funsupply.com.au/pages/Kite-Surfing-in-Darwin.html