I never looked into Snap Creator too much, but it looks like it was originally a 7mode framework/software for developing your own data protection management:
https://kb.netapp.com/support/s/article/ka21A0000000iYzQAI/faq-what-is-snap-creator?language=en_US
I see references to Snap Creator in the context of ONTAP 9.x (cDOT) operations, so it looks like it's an on-going supported technology.
SnapCenter is the consolidated/unified console for managing/viewing/etc snapshots being orchestrated by various NetApp technologies. Here's the overview page from the documentation center:
http://docs.netapp.com/mgmt/topic/com.netapp.doc.ocsc-isg/GUID-0CC54DEB-2A3B-4E98-8615-C97A225FEB2A.html?resultof=%22%73%6e%61%70%63%65%6e%74%65%72%22...
A lot of what used to be individually managed/orchestrated from the various SnapManager for X products is getting integrated into SnapCenter (such as VSC 7.0 backup/restore). We (my shop) are definitely on the path to implement SnapCenter as part of our operation...
Hope that helps,
Chris
