I did upgrade my license, partly for the iPhone RAW (though I sold off all my iPhones this summer, partly because of the lack of PhotoLab RAW support!) and the scanned negative conversion, which doesn’t work in PhotoLab on macOS for now.
So real world experience. PhotoLab 9 is much slower and clunkier. I was delighted with PhotoLab 8 and have been very disappointed with PhotoLab 9. Masking and repair seems to slow PhotoLab 9 down to a crawl, much worse if one uses AI masking (don’t even enable AI masking, if it’s in the history of an image even disabled, all editing will turn to molasses).
Hopefully PhotoLab 9 will radically improve, there have been duff releases in the past when the repair tool was new. Based on what I’m seeing though it may not be until PhotoLab 10. If you can sit it out, you probably should.