I'll also point out that, even if the primal chaos is indeed 1-C, you haven't really provided evidence souls would scale to that. Something qualifying for Tier 1 based on statements about higher dimemsions doesn't mean that everything else qualifies for it, too. This is only the case if the verse makes it clear that -all- higher-dimensional things have infinitely more power compared to lower-dimensional ones. If it doesn't, and you have to argue it qualifies using other types of evidence (Which is evidently the case here), then that opens up the possibility for things of the same dimensionality having different ratings, even if it's the same verse.
In fact, thinking about it a bit more, I have a question related to that second point, too: The scan saying that souls are 9-D forms also says that they not only originate from a higher dimension but also return to that place after death. This would imply that these souls, despite being higher-dimensional, can still exist in the normal universe, no? This is probably a minor point (Comparatively, at least), but I feel it's worth noting regardless. I know shit about Devil May Cry, so, obviously open to being corrected.