When I first got my N9 I was having a wifi connection issue at my house. It would work at public wifi spots but never at home. So I tried several things on my own, asked for help from my Tweeples, Nokia Cares etc…
I even (gasp) turned off my WiFi password and left it wide open but to no avail. After a few weeks of screaming, cursing, and sweating I finally found the issue.
My wireless router settings in “Wireless Mode” were set to Mixed: accepts 802.11b and 802.11g connections once I changed my wireless settings to Legacy everything has worked great!! I could even password protect my network again!!
My router is a Westell Model 7500 and your specific router may or may not have a “Legacy” setting on it at all, but learn from me and try to change your “Wireless Mode” settings.
Normally you can get into your router by putting http://192.168.1.1/ in your address bar. There is another less used IP address for routers but normally http://192.168.1.1/ works just fine. If it doesn’t work for you a little bit of internet searching should easily fix that problem.
Hope this helps your WiFi issue! Good Luck!