Should 999 be Thaumiel? Because calming down 682 is a pretty big deal.
Posts about specific SCPs should go in the discussion thread for the SCP in question.
That said, I would say no, because SCP-999 is not used to contain SCP-682, and in fact doesn't actually manage to make 682 less deadly. I recommend consulting the Object Classes guide to get a better handle on how Thaumiel works.
I looked at this and honestly thought it was a stupid question. But after a few minutes, I could see how it could be classified as Thaumiel.
However, I do not think it schools be classified as Thaumiel. SCP-999 could be VERY helpful when it comes to the recontainment of SCP-682. But could it recontain 682 by itself? Very unlikely. Not only that, but 999 could only help recontain SCPs that are "ticklish", which I don't think there are many of those.