Lyman, as there are no requirements for a ‘pusher’ (or any other device) in the stall certification requirements, then no waiver is required. CS 25 / FAR 25.201 onwards.
The circumstances leading to this accident do not appear to differ significantly from the certification demonstration requirements, although the lack of initial recovery action (post stall 'identification') and trimmed condition may represent aspects which were not, and perhaps did not need to be demonstrated.
testpannel, to ease your headache, and for clarification – no recovery device (stick push or otherwise) is required at the stall; I think that most pilots understand that a shaker is not a recovery device.