9" vs 10" drum brake spindle question

RE your original question:
will I need to get anything else to put them on the car
Regardless of which kit you get, you will need to upgrade to a later dual reservoir disc brake master cylinder, proportioning valve, and MC line kit. If you have power brakes, you MAY also want to consider upgrading the booster if you choose to stay with PB.
The good Doctor has all the parts.