I really don't understand where all the assertions that Kyubey is male come from. Kyubey does use a usually male first person personal pronoun (boku - 僕) but that is not strong evidence by itself since reverse traps and tomboys regularly use the same word. To my knowledge there are no other clues as to Kyubey's gender, at least within the first 10 eps of the anime. Any translations that use 'he' 'him' etc. are simply making assumptions necessary for smooth dialogue.