date = CreateObject("roDateTime")
There is no solution. The box doesn't have a battery backed-up RTC. I doesn't know the correct date/time until it establishes an Internet connection and contacts an NTP server. If your app can't operate without the correct time, you either have to wait for Internet connection to be established or exit if the connection hasn't been established. You can't rely on roDateTime unless the box is able to contact the Roku NTP server.
Perhaps you can check for the date/time, and if it is the default date you receive when there isn't an internet connection available, simply not use the data and check it again later in the application.
Although why your device would require the internet but not be able to access the date/time server, sounds like a critical flaw in your internet routing service/gateway/proxy maybe?