RE: Isonic 135 2006
The '06 Isonic 125 should be even better than the 135 as I think it will have a little better range on the top end (better over the chop).
Not sure how well it will do with a 9.5 m2 rig, but I had no problems with the '07 Isonic 122 with an 8.5 m2 Race sail and 32 cm Lessacher Duo weed fin while I was in Bonaire. As I said, the 8.5/Is 122 was pretty much the planing champ amoung recreational sailors.
Should be a geat value, and if it really does not do well with the 9.5 m2 you could drop back to a 9.0 m2 and I think that would be a very "balanced"combination. Add a slightly larger (4-6 cm) fin and you sould have a very easy (compared to the HS 125) to sail board that planes early, goes fast, and has a very wide range of use (down to 5.5 or 6.0 I'd think.
Hope this helps,