This is the requirements for hydromassage tub bonding:

All metal piping systems and all grounded metal parts in contract with the circulating water shall be bonded together using a copper bonding jumper, insulated, covered, or bare, not smaller than 8 AWG solid.

CPVC is not a "metal piping system" and there are likely 'no' "grounded metal parts in contact with the circulating water" ... which means ... no bonding under those conditions.