Yes, the Sony Alpha A9 III is compatible with the Transcend 700S V90 128GB.
Transcend 700S V90 is V90 class. Clears: XAVC S HD (100 Mbps, requires U3); XAVC HS 4K (280 Mbps, requires V60); XAVC S 4K (280 Mbps, requires V60); XAVC S-I 4K (600 Mbps, requires V90); XAVC S-I HD (222 Mbps, requires V90).
“This camera supports CFexpress Type A memory cards and SD memory cards (UHS-I, UHS-II compatible).”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)