Sorry, but your messages are very hard to read.
The i7 6700 is a bit old and a bit underpowered for MSFS, but with medium settings it should work. Not clear if with "should go I9", you mean replacing the cpu only ( assuming it's even possible ) but, as a general rule, you want to have the CPU and the GPU balanced: no use placing a powerful CPU with a weak GPU or vice-versa.