Yes because Naruto taught a non genin a S Rank technique that was taught to him by a Sannin.
Consider Naruto's level of intel, every Sensei he's had had to dumb down explanations to the lowest level possible so that he can at least get a grip on it. Konohamaru at the time wasn't even a Genin.
Naruto can teach the Rasengan to shit, and shit will be able to do it.
If we go by your logic every shinobi can be a genius
dude i am sorry to say that you have some wrong concept
1. rank s is not used in case of technique. it is used in case of mission.
2. you can teach a student a master ranked ninjutsu when you are jounin. naruto begun to teach konohamaru after becoming a genin.
3. konohamaru was a genin that time when naruto taught him the rasengan.
yah one thing i wanna to add that my point number 2 may be not absolute rule but according to konoha's teaching technic it seemed.....