Jman and Kakashi knew for sure. Kakashi isnt stupid (at least i dont see how he couldnt have known) and Jman is just absolutely useless if he didnt figure it out too. Though we havent seen it, it would be "known" by both of them that Kushina was pregnant and that she was the jinn of the 9tails (kakashi may not have known that but Jman did for sure i bet) for the 9tails and both adults to disapper and we all of a sudden have an orphaned lil jinn, then its just obvious to someone like the two to them who Naruto is.
Also, i have been rereading the manga and i could have swore i read somewhere that nobody knew about Naruto but just the jonin and higher ups, that way they knew to protect him...I still dont see though how not telling ppl who Naruto is (talking about 3rd hokage), being Minato's son, was beneficial to him in any way growing up..i mean ya it protected the 9tails but someone could have told the villagers at least that he was important or something to lessened his lonliness in childhood...sorry off topic but i have always wondered that.