We don't have any specific requirements for capture methods. Dolby Atmos for Virtual Reality uses mono and stereo objects in addition to the 9.1 bed channel configuration found in theatrical Atmos mixing. Currently, an ambisonic decoder is not part of Dolby Atmos Production Suite but they can certainly be utilized in the Dolby Atmos post-production environment with third-party decoders such as those available from TSL and Harpex.
Please also see FAQ articles
For post-production, we encourage you to capture mono and stereo sources so that you can associate each such source as an object and mix the content the way you want.