CBDa definitely crystallises.
I believe @Photon_noir can go into more detail, but I’m under the impression that due to CBDa having 3 active groups (two hydroxyl and one carboxyl), it can form at least two different crystal lattice structures.
THC having only one hydroxyl group can only form OH-HO dimers, but CBD having two can keep reacting and form a crystal lattice, CBDa having three can form multiple different crystal structures.
Perhaps Photon will chime in and correct anything I’ve got wrong or just drop some more information, but I’m absolutely certain CBDa will crystallise.