Tribeca 2008

Hello all, just purchased a 2008 LTD. Sold Ford Explorer to get something more reliable and efficient. Always wanted a Subaru big enough to hold camping/picnic gear, pull one wave runner and hold my 6'3'', 215lb frame. Need to know what type of hitch to purchase. Must it be from the dealer or is aftermarket ok. Also will B9 attach to 2008 frame? Not much detailed info to be found.