Wheel and tire fitment

I'm finally ready to pull the trigger on some 275 70 18 wheel and tire package. The only problem I'm having is that the shops here in sac and online won't combine that package for me. They are saying that the tire is too small for a 18x9 wheel. They are tell me to go 285 65 18. Bfg ko2 are the tires I'm trying to go with. Site says the are max width 8.5 and so are the nittos. I'm I missing something? Plenty of you are running 270 75. Any suggestions

 

I have not seen any limit to 8.5inch wide wheels for that size. All of the 275/70-18s I just checked online show they can be mounted on rims 7 inchs to 9.5 inches wide.

Check this, BFG in that size and look down and to the right to see the rim widths it fits- you will be fine with 9 inch wheels. Plenty of people running 275/70s on 9 inch wheels.
https://www.discounttire.com/buy-tires/bfgoodrich-all-terrain-t-a-ko2/p/29052

 

I've called tire rack and real truck accessories and both said it's not possible. Thanks for the link. I'll call them hopefully it will work out.