Hey Blueseven,
The Crossbow is a 4 line bridled kite, unless your mate carried out some extensive mods.
It will be OK to learn on if you rig a flagging safety leash to the front line and then use a big board. At 90 kegs, ypoure a big fella and will be better off on a 12m Crossbow or similar for average winds of around 15-25knots. The 9 will be fine too but depending upon the board you are going to ride, will probably be in the high twenty knot range.
It will be fine for basic flying and learning in 15 knots, but on the board you will need more. What state do you live in?
Good winds,