Yes, the Panasonic Lumix G9 II is compatible with the SanDisk Extreme PRO SD UHS-II V90 128GB.
Panasonic Lumix G9 II's SD slot accepts this card directly. SanDisk Extreme PRO SD UHS-II V90 128GB is V90 class. Clears: MP4 4K30 LongGOP (72 Mbps, requires V10); MOV 4K/C4K LongGOP (200 Mbps, requires V30); MOV 4K/C4K ALL-Intra (400 Mbps, requires V60); MOV 4K/C4K ALL-Intra (top tier) (600 Mbps, requires V90).
“Motion pictures with 400Mbps or less: External USB-SSD, SD memory card with Video Speed Class 60 or higher Motion pictures with 600Mbps or less: External USB-SSD, SD memory card with Video Speed Class 90”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)