1) There was a guy I met who is shia who had piercing on his ears. He told me this is okay in shia islam. Is that true? Do all marajaas accept this or reject this or are they divided on this topic?

2) He wears earings but he is living in the USA where it is not considered inappropriate so is it halal for him to wear earings? If yes then where are justifications for it? (I mean from quran and hadith of ahlulbayt) Is it true that one of the imams wore earings?

1) We have hadiths that it is recommended to pierce the ears of a newborn. However, scholars have understood this as just piercing the ear, and not wearing and earring for an adult man. Secondly, if something is considered socially inappropriate (and makes one associated with a negative culture), then a believer is required to avoid that.

2) I am not aware of a hadith that says any of the Imams had earrings when they were adults.

Now in the USA, honestly, wearing earrings is associated with a negative culture. That’s why most American professionals, officials, and people respected in their communities don’t actually ear earrings.

In addition to that, in our era, earrings are considered a feminine adornment in most societies, and we have hadiths that prohibit men from appearing like women.