In the short novel by Cinthio, Otello is a delinquent, and the story isn't much like that by Shakespeare. Moreover there is a little problem: in Venice the word "moro" meant: "Arab/North African" and "inhabitant of Morea" (Peloponnesos, in Greece: in fact in Venice there is a quarter called "Contrada dei Mori", and there lived the Greeks). So, in the story by Cinthio, the geographic origin of Otello is not completely sure.
About the question if there were Moor kings (well, Venice hadn't kings, it had the elctive doge, the title is comparable to that of duca = duke), no, there weren't. I don't know if there were Moor generals/admirals, but I don't think.