Here’s something I tried that might help in some cases for refining fur (and maybe hair?) when using AI masking in PL9 - it certainly helped in one of my images that I thought I was only going to be able to do in Photoshop (because of it’s advanced edge refining tool). Ironically I got this tip from using AI masking trick in Lightroom but it seems to work in PL9 too - worth a try - let me know how you get on. I tried this because I really struggled to refine my AI mask with control points (If anyone has any helpful tips let me know but I think it was just the subject and background were very similar luminosity and chrominance that made it difficult to do it this way in that case.)
Use the AI masking tool to select your subject with either the hover tool or the specific tool. Then add a sub mask using the rectangle AI tool - then press the invert shape tool and then the invert mask tool - it seems to do a better job of refining the fur. If anyone has had a particularly tricky fur image could they try this and let me know if it helps please?