Hi BAMoh......sorry, didn't see your question in the quote.
I had some success and some failure by configuring the cameras to reboot every 24 hours. If they lose connection then they sometimes will reconnect when they boot. While I have two 2630L cameras three 2330L cameras that all reboot every 24 hours, two of the 2330L cameras have gone awol precisely at the time of a reboot and have been gone for days now so I'm on the fence about using that solution.
I think the more solid solution is that I recently put my DSL modem and router/access point on a UPS system that will hold them up for hours. The cameras are not on the UPS so they will definitely power off in the event of a power outage. So long as the power outage doesn't exceed the holdup time of the UPS the modem/router/wap and wifi network will be up and waiting for the cameras when power is restored. In the case of my missing 2330L cameras, I'm waiting for an outage so that I'll be able to disable the reboot feature when they come back.
Sorry, never had a 900 series camera so I can't compare.