Unfortunately, there is no way to transfer information from TurboTax Online to TurboTax CD/download. TurboTax Online can’t save to the .ttxx format, however you can get a .pdf file with your complete tax return information for you reference. Here is how you can print a copy of your tax return in TurboTax Online: https://turbotax.community.intuit.ca/replies/2648070
It should not be difficult for Turbotax to program a conversion between the online and software platforms. I strongly urge this to be added in the future.