According to NetWorker 9.1 GA announcement:

Dell EMC NetWorker 9.1 - General Availability Announcement

There is NetWorker Snapshot Management for Unity Support.

But when I check below documents, it did not mention about Unity snapshot support with NetWorker.

1) DellEMC NetWorker snapshot management white paper

https://www.emc.com/collateral/white-papers/h1888-networker-snapshot-mmgt-wp.pdf

2) Networker 9.1 Snapshot management and integration guide 2016 Dec

docu81541.pdf

Please kindly advise, thanks.