A presidential pardon would only get Roberts off the hook in the USA. It would however bring an international public spotlight to the effect that the highest USA court official had a demonstrable need to be pardoned for underage human trafficking, which probably does not make the USA or the USSC or President Trump or Roberts look very good to anyone. It also would serve to tip off Irish authorities that Roberts is likely to have been guilty of illegal adoption and human trafficking under Irish law, and therefore could well trigger an indictment in Ireland and a request by Ireland to the USA for extradition of Roberts to Ireland for prosecution in Irish jurisdiction. That would all be rather messy IMHO and have a serious long term effect on Irish-American diplomatic relations...
(see also: Ex Parte Grossman, 267 U.S. 87 (1925) for a definition of “offenses against the United States”)
Wow, I didn’t think about the international ramifications. So he’s 100% compromised. I don’t Trump would ever think removing his children from their only home would be in their best interests. So what happens with a permanently compromised Supreme?
Maybe wait till the kids are of age, and then slam Roberts and get him thrown off the court?