if u plan on porting it later.. go ahead and get the 9's
when my motor was stock (with bolt - ons) i ran a 22' 8 paddle hauler with a +6 swingarm (im 180lbs)
when shee got ported , i ran 22' -11-8 9 paddle hauler sls
id go ahead and get the 9's.... i like to run 8 inch rims, but if ur going to dune more 10 ' rims are better.