I would like to knew what type of patch to use on cracks before painting a inground pool, as well as should I strip all paint and old clauking? And what type of paint should I use so I don't have to do it every year?

My first guess is an Epoxy paint system:

pool paint | swimming pool paint | epoxy pool paint | diy pool paint

Yep, remove the old paint. Home Depot has mechanical paint removal systems that can be rented.

Yep, remove the caulk.

Surface prep will be the biggest issue. Etching will have to be done using Muratic acid or Drylock etch or whatever this manufacturer reccomends.

I'll bet that a expansion cement such as Rock-ite can be used to repair the cracks. A diamond rasp can be used to make the cement smooth.

Prepping is the hard part.