I see that many people here use 17x9.5 wheels from ZR1 on front with big nasty wheels adaptors. I don's trust them , so I want mount on front 18x9.5 custom wheels without adaptors.

So , anybody can tell me what ET i need to drive fast and safe

 

Just get the same backspacing as the other guys with 9.5" fronts, and then pick the right tire for your diameter that gets you the closest to their overall dimensions as possible. As long as the overall dimensions are the same then you'll have similar experiences. Use a wheel/tire calculator to do the math.