Posting my (positive) experience getting this fixed, in hopes that it helps others.
I purchased a (NTM) 2018 CX-9 GT in August ('21) and had noticed some cracking in the upper right corner.
I thought the car was good enough at the time to buy, all else considered, and this was a trade in to a German car dealer so they didn't care about fixing it.
After reading about the TSBs covering the 2016, 2017, and 2018 model years, and the SSP covering only '16 & '17, and based on some posts earlier in this thread, I reached out to Mazda corporate about it via email. They replied, basically asking if I had spoken to my dealer and if not, to start there.
I took it into my local dealer (of which I only have one). I printed out the TSB, highlighted the section about it being a faulty display; printed out the SSP; printed out a full-page color photo of my screen similar to the photo above. I brought these items to the service counter and explained that there was a bulletin on faulty displays, that the SSP didn't cover my year explicitly, but I had heard/read about Mazda corporate covering the '18's on a case-by-case basis.
There was some question about whether I purchased the car from them (no), whether I was the original owner (no, I am #2), whether the car is under warranty (no, 45k miles). I made sure to mention that I
would have bought this car from them if they had it, but their inventory is bone dry and they know it all too well. Long dialog short, I basically was asking the lady at the service counter to be my advocate to Mazda corporate on this issue, and that they had asked that I make the request through a dealer.
The lady at the service counter mentioned that she wasn't sure what they could do, as the parts and labor cost money, etc, etc. I mentioned that I thought Mazda corporate would reimburse dealer for all parts and labor, and she was like, oh, well yeah, but let me talk to the service manager about this and see what we can do. After she had a brief convo with manager, she came back out and said they'd submit the issue to corporate and went through all the right motions - namely, came out to car and inspected the display to make sure I didn't hit it with a rock, took more info (mileage, VIN, etc).
The sales guy I had been chatting up while waiting for the manager conversation to end also came out to car with us and said he had never heard of this issue before but was pretty interested in seeing it first hand. I figured it would be good to have a revenue generator at least in the orbit of this conversation, somehow.
They submitted the issue to Mazda. In the meantime, a new crack started developing this month amidst some pretty cold weather. It's in the lower right now.
About four days after I had taken it in, I heard back that Mazda would cover it all if I paid a $100 deductible. "Absolutely," says I. Considering the part alone would set me back about $1800 or so, this was more than acceptable to me. Based on the language they were using, I'm guessing Mazda corporate is making a claim against their own insurance, but who knows.
By the time I took it in for the scheduled service, the crack in the lower right had grown.
So based on previous posts I read, it would seem cold weather has certainly aggravated this. I travelled South to buy the car, and brought it back North where temps are considerably colder than what this car has been used to by a pretty wide margin.
The new screen is in and crack-free so far. The part number listed on the invoice is TK49-61-1J0B. The line item says, "The factory warranty covering this repair has expired. Assistance has been provided as a one time goodwill gesture by the manufacturer." The invoice also lists process number AL009a, S99, D99, labor op XXS1ZXRX, .2 hours. This info matches the TSB items, but on my invoice was listed in the notes, so this could merely reflect the information I provided to them vs. what they were operating under from Mazda's coverage.
Anyway, new screen is in, no cracks, looks great. Kudos to my local Mazda dealer and Mazda corporate for backing up this claim. Good luck to any of you pursuing a fix for 2018 models! Totally worth it to ask the question, but the sooner the better, I'm guessing.