For VR, it makes no difference in which format your multichannel sound is stored, as long as the interpretation of the directional information is done correctly (which again depends on the application).
Both variants (4CH and Ambisonic) contain the information about which direction a sound comes from. They just use a different description of the directional information.
With Quadraphonic sound, the sound comes from four fixed positions, and with the Ambisonic format, the directional information results from an intersection of the W/X/Y/Z axes.
With sound over stereo headphones (which is common in VR), these sound sources are then remixed, depending on the viewing direction.
But if you really insist on a "real" Ambisonic format, you can always convert the four-channel sound into an Ambisonic format yourself.
However, this is definitely not the job of Blender, but of professional audio tools (hardware/software).