IMO, these latest changes also look good and serve us well.
At first, I was a bit reluctant about putting "Running Mac OS 9 on unsupported hardware" as a child board instead of it being a main board, but when I browsed the main forum page, it did work very nicely, because we see a link in there anyway that mentions it, and even takes us straight to that board if necessary. Plus, it makes sense for it to belong to that main board you moved it to.
Now, I do have a suggestion...
I think the board name "Mac OS 9, Hacks, Upgrades & General Discussion" can probably be improved. I think the merge itself is fine. Just the name can probably be better. How about simply "System and Hacks"? It is as clear as "Hacking the System" was, if not even clearer, and also makes it clear that it is a board to discuss the System itself, meaning Mac OS 9, without us having to spell out "Mac OS 9" outright, which otherwise feels a bit repetitive, since the whole forum is already about Mac OS 9, so "System" keeps it short, sweet and to the point.
"System AND Hacks" implies we will always be talking about the System, be it in a general way, or with regards to hacking it to get it to do things beyond it originally could.
The name also makes it clear, in as brief a manner as possible, that, by saying "System", we are talking of the OS itself, rather than any other software, so it contrasts nicely with the "Software" board, which is meant to address every other software being run under Mac OS 9.
And, again, if the board name uses the term "Mac OS 9" instead of "System", it is not as instantaneously clear what it may mean, because each board of that section is already addressing something of Mac OS 9. By calling it just "System [and Hacks]", there's immediately no doubt what it is about.
One more thing, the name of the "group" of those boards is currently set as "Classic Mac OS Discussions". I think it should be "Mac OS 9 Discussions". I don't see why we should use the term "Classic" there, and even if we want to address OS versions that predate 9 in a given topic/thread, that should be fine, since everything here is OS-9-centric anyway: when discussing older systems, it normally will be by comparing it to 9, such as when we talk briefly about OS 8.6 and whatnot, or when we discuss the nanokernel of Mac OS 9, which is also used in 8.6, and so on. People also have both System 7 Today and the Macintosh Garden if they really want to insist, they can very well participate in multiple forums, while we keep the focus on what matters to us here.
The term "Classic" applies best to the emulator of same name used to run Mac OS 9 and earlier. While the expression is colloquially used "out there", it is nonetheless confusing, and I think it is detrimental when we adopt it when we simply want to refer to an OS that has a proper name, that being "Mac OS 9", no more, no less.
And that's it! Hopefully I could convey my thoughts clearly and reasonably?