Creating his own techniques? that's your intelligence feat? deidara created the majority of his, is he smater than itachi? lots of ninjas create techniques, it has little to do with the intelligence factor.....
Minato put the kyuubi in his son because he wold TOLD by jiraya the sage prophec.y.. that a student of jiraya will become the saviour of evil..... That night , since he was about to use rds, he knew the saviour wasn't himself.. and realized it was his son.. he literally said this note you.... Tobi would eventually come for the kyuubi... and if he killed it, it would be revived eventually as he said.. meaning the SAFEST place for it , would be inside the child, who he just realized won't die, because he is going to save the world..
That's like Itachi having a prohecy, a cheat sheet on how sasuke's life would go.. ofc he wouldn't make any mistakes.. because itachi used pure strategy with nothing to help him ...thus things didn't always go according to plan... because without a prophecy.. you CANT predict everything.. he couldn't predict kabuto would revive him with edo tensei... many things out of his scope happened that ruined his plans
But if you want to talk about creating jutsu, Itachi created Transcription seal amaterasu, specifically for tobi.. a jutsu obito himself didn't understand.. a fuinjutsu that implants an ability into another and sets a pre activation
He most likely created the exploding bunshin jutsu, considering Asuma's reaction, like he had never seen or heard of something like that before... "The clone exploded?!!?"
...NOTE AGAIN... Itachi after academy, had no teachers to really teach him ninjutsu.. he was ALONE after 13... meaning he taught himself all of that..... Kushina taught Minato almost all her seals.. Minato had a sannin teacher (Jiraya)
The sheer difference in intelligence and talent between the two ninjas is obvious