The site has a contact page. If you have a legitimate reason, try asking nicely. Otherwise just learn to cope with the fact that the internet is forever.
As far as I know, you can't. The links aren't indexed though so if you delete all references to them on other websites you would get pretty close to shoahing it.
Also, according to AOjew at least, catbox eventually deletes older content.
[ + ] Neral
[ - ] Neral 3 points 1.9 yearsJun 12, 2022 11:28:23 ago (+3/-0)
[ + ] Her0n
[ - ] Her0n 2 points 1.9 yearsJun 12, 2022 11:23:51 ago (+2/-0)
Better off asking the reddit jews, seeing as they are constantly scrubbing the truth from the internet.
[ + ] GloryBeckons
[ - ] GloryBeckons 1 point 1.9 yearsJun 12, 2022 13:28:36 ago (+1/-0)
[ + ] Steelerfish
[ - ] Steelerfish 1 point 1.9 yearsJun 12, 2022 11:26:29 ago (+1/-0)
[ + ] lord_nougat
[ - ] lord_nougat 0 points 1.9 yearsJun 12, 2022 17:10:42 ago (+0/-0)
[ + ] v0atmage
[ - ] v0atmage 0 points 1.9 yearsJun 12, 2022 13:14:04 ago (+0/-0)
Also, according to AOjew at least, catbox eventually deletes older content.
[ + ]deleted
[ - ] deleted 0 points 1.9 yearsJun 12, 2022 11:50:34 ago (+2/-2)
[ + ]deleted
[ - ] deleted 0 points 1.9 yearsJun 12, 2022 11:31:38 ago (+0/-0)