Doing a quick search does show MAC clients are Supported, you can narrow down specific ONTAP, SMB, and OSX versions on the NetApp Interoperability Matrix.
Also wanted to point out this specific tidbit that might be useful:
Guidelines for using automatic node referrals with Mac OS clients
"Mac OS X clients do not support SMB automatic node referrals, even though the Mac OS supports Microsoft's Distributed File System (DFS). Windows clients make a DFS referral request before connecting to an SMB share. ONTAP provides a referral to a data LIF found on the same node that hosts the requested data, which leads to improved client response times. Although the Mac OS supports DFS, Mac OS clients do not behave exactly like Windows clients in this area."