CBS is cinder block? (Today CMU).
Hard to say without seeing it (pics?)
What's been done before? How many cracks?
Elastomeric waterproofs and will bridge small existing and future cracks.
It's the best product for your type application and is usually recommended.
It's nice to keep down moisture migration in damp environs.
If your block were originally painted with block filler and coated with good exterior paint, leaving no pinholes showing in the paint, then the cracks would be the only biggee.
Multiple small cracks and still have pinholes, then elastomeric for sure.
YES, since you are on the coast.
but go visit a few local paint shops like SHerwin Williams and others and get different opinions.