Welcome to the Community,
while vSphere runs in evaluation mode it offers all features of the Enterprise Plus edition.
I may be wrong, but from how I understand VAAI it comes into play on already existing datastores, but not for creating them. At least I can't find anything about that in http://www.vmware.com/files/pdf/techpaper/VMware-vSphere-Storage-API-Array-Integration.pdf.
André