It depends on the RAID configuration used. It is suggested to use RAID 6 with hot spare for each enclosure. So, for this combination, a total of 468 TB free space (9X(16-2-1*)X4) will be available.
*In RAID 6, 2 disks are used for parity and 1 disk for hot spare in each enclosure.
Please note that the size of available space may vary based on the space reserved for the system.