You usually don't need any special plugins/VIBs on the ESXi side to make VAAI work with specific storage devices. It's all implemented in standard SCSI controls that the the storage array either supports or not.
I have a question regarding the use of VAAI and an EMC VNX. So from the host command line you can check vaai status and it shows the different vaai components that are supported. Just because they are supported doesn't mean vaai is working, right?
If the output of esxcli storage core device vaai status getindicates that VAAI is supported for ATS/Clone/Zero operations (Delete is a bit of a different story), then you can safely assume VAAI is working.
To confirm this, you can check (r)esxtop while you clone a VM or create an eagerzeroedthick disk:
vmkfstools -c 5G -d eagerzeroedthick /vmfs/volumes/MY_VAAI_DATASTORE/testdisk.vmdk
During that check the (r)esxtop storage device view ('u') and add fields for displaying VAAI stats ('f', 'o'), remove other fields if it doesn't fit on your screen. While the disk is being zeroed out you should see that the MBZERO/s counter for the LUN is high and the normal MBWRTN/s counter does not show any significant activity.
If VAAI is not being used actively, the above vmkfstools command creating the disk will result in normal non-offloaded writes and the counter values will be reversed.
Also be aware that for copy/cloning between VAAI capable LUNs, source and destination need to have the same VMFS major version and blocksize, and both LUNs need to be managed by the same storage controllers. Otherwise it will automatically fallback to non-offloaded read/write operations on the LUNs.