Panasonic recommended to use UHS-II V90 SD cards, so you can choose these cards:

• SanDisk Extreme PRO SDXC UHS-II
• Lexar Professional 2000x SDXC UHS-II

Popping in a day late but I'd be cautious about just chasing the highest V-rating. I learned the hard way that some high-speed cards get incredibly hot in compact bodies like the S9, leading to dropped frames or even write errors mid-clip. It really soured my experience during a summer shoot last year.

• Are you planning on shooting a lot of 6K Open Gate or mostly high-res stills?
• Is sustained write speed or total capacity more important for your workflow? Reliability is way more important than peak speed numbers imo. You might want to consider if you actually need V90 or if a high-quality V60 would be more stable for your specific use case. Some cards handle the heat better than others tho, so make sure to check the operating temps.

SanDisk Extreme PRO SDXC UHS-II is the best choice.

Get any UHS-II SD cards are OK.