There is a large archive of non Roman fonts at the Yamada web site. Please click here . In the US there is no mechanism or procedure for certifying either translations or translators. There are certified interpreters at the Federal level and in some states, but they are beasts of a different color. There are rare occasions when the certification letter which accompanies a certified translation must be notarized, but this is a rather different issue.
Nobody does, because there is no Ethiopian language.
People from Ethiopia speak one of 82 possible languages. There are media in Amharic including radio, television and newspapers. English is used in higher education. So, to reach the widest audience the appropriate language would be Amharic, while English would be used for educated Ethiopians. However, it is important to note that although someone is from Ethiopia they do not necessarily speak Amharic.