I bought a 2021 CX-9 GT back in November 2020. I thought the way to go on crossbars was OEM but the tailgate could not open all the way with the skybox 18. I did a little more research and just installed the Yakima Ridgeline towers with the appropriate clips for Mazda. The clips for the flush mount side rails have a nub that needs to go into the holes used by the OEM crossbars. This limits the placement of the towers on the roof rails. Yakima's instructions say to use the rear holes but this would have moved the crossbars even further back than the OEM bars. I chose to put them in the forward holes on the side rails which moved the bars about 2-3 inches forward. This gives me enough clearance to fully open the tailgate. I can't see how using the forward holes creates a safety issue.
Hopefully, my pain is someone else's gain on this one. Wish I had started with these crossbars.
Hopefully, my pain is someone else's gain on this one. Wish I had started with these crossbars.