hi
about cataract surgery and the choice of the kind of implants , for pool i would strongly suggest you to avoid multifocal implants, and to choose mono implants. You'll need reading glasses but the result will be much better for pool.
(the vision quality with multifocal implants is actually a lighting-dependant compromise ...So, for pool players, best are mono implants . If you had low to medium myopia , to me -optometrist-, multifocal implants are a no-go if you want a good sight and global confort ).
About contact lenses & low stance, it depends of the contact lenses kind : with monofocal contact lenses -for myopia or hyperopia- , you'll be fine, no stance problems.
But if you need contact lenses for astigmatism and/or multifocal contact lenses, for some technical reasons , yes, you could have to modify your stance , it depends of the lenses , because the center of the lenses must remain +/- centered on the cornea and/or to respect a certain axis/orientation to reach a good vision .