We don't have that data for volumes and aggregates. Not sure if OCUM has that info anyway.
For volumes, I remember we wanted something like that and it wasn't available. I do see a discovery timestamp, but not sure if that's a good enough indication (It is possible to use it in that context).
>> So if that something OK ( 15mins, max difference between it got created in filer and discovered in OCUM) feel free to use objCreationTimestamp
From WFA side, we currently cache this objCreationTimestamp (the one Adai and Yaron are mentioning) as discoveryTimestamp as shown in picture below. This is available from WFA 2.0.1 release and only for volumes of traditional Data ONTAP (7-mode systems)
Also, I have personally not seen anything like a creation timestamp exposed from ONTAP in APIs at least.