18" front fitment with wider than 8.5" width is quite possible, as long as you make sure to get a wheel that is optimized for front wheel fitment, with flatter spoke profile and greater brake caliper clearance. Different mfrs call their profiles with different names. Examples:
Enkei calls theirs "F" face vs. "R" face. Differentiation is self-evident.
Konig calls theirs "A" profile vs. "B" profile. Similar to Enkei above.
Other mfrs generally have similarly profiled designs, but these two mfrs are what I am familiar with.
Finding an 18x9 "F" face or "A" profile is more difficult, but not impossible. If that is really what you want, I'm sure you'll find some that might work.
Now then... what do you gain with an 18x9 vs. 18x8.5? Realistically, if you limit the tires to no wider than 255, that extra 0.5" don't really buy your tires that much better lateral support. IMO, the only reason for wider than 255 is RWD power handling. So... if you want tire rotation capability with a square setup and mount 265+ wide tires all around, then... yeah, 18x9s might be of interest to you. IMO, it is a pointless exercise with a 2.0T Stinger. We run square 255/40R18 A/S tires on 18x8.5 for street use on our
G70 6MT Sport, and it is a sweet setup that balances steering effort, power handling, and ride comfort. Switching to 18x9 (with or w/o wider tires) would just add weight with no appreciable real-world gains.
Now, for a 2.5T souped up for some serious heat... okay, maybe. Nothing wrong with experimenting. If I ever go nuts with HP
mods on my 2.5T (BTW, not really my thing), I would keep the 18x8.5 up front, and switch to 18x9.5 for running phatter tires out back. RWD power handling is the whole reason for going staggered.
BTW, 255/45R18 seems rather tall IMO. That's just me. Up to you to decide on your own ride.