Hello and welcome to the forums
No one knows how i9 will perform and even when it will be released.
Also if you want to wait,you have to wait for ever because this stuffs change everyday and there is always something new around the corner
I would worry about the i9's heat output if/when they put it into a laptop. I've heard the i7 having some troubles already, but that's probably due to its combined use with high-end graphics cards. Would the i9 just multiply those problems?