CodeWeavers can't just integrate the latest Wine changes into Crossover without further fixes and testing, otherwise all sorts of things could break. Even Linux distributions won't ship what's in a main
branch to users immediately, because the main
branch isn't considered stable or even beta quality in the case of Wine, and beyond Wine releasing what they consider a "stable" version (Wine 9.6 in this case, which they did do in early April) there are additional fixes, patches, and other software and testing that's done downstream (in one example, by Linux distributions or by Valve, or in our case, by CodeWeavers). Running Wine yourself can be very finicky, might require manual integration with things like D3DMetal, GPTK, etc, and that's what Crossover is for and why we pay for it.
CXPatcher let's you try some things ahead of when CodeWeavers will consider it stable and put their stamp of approval on it -- but it doesn't seem to include a newer version of Wine.
The good news is that CodeWeavers are working on this; the latest blog post talks about a Preview version of Crossover (invite only, unfortunately) that includes Wine 9.6 and thus the patch referenced (even mentions Tekken 8 by name in the post!), but no details on a non-preview and/or generally available release date.