First of all, forget using your 9.0 dedicated slalom sail for wave riding. You should need a much lighter and softer sail without cambers (with on/off power) to vastly improve the manoeuvrability while riding the waves. The slalom sail is way too heavy, rigid, powerfull and costly to be ridden in waves...
You have several options depending on what kind of wave board you want to ride: short board or long board.
1) For true waveriding, better consider a 2009 Evo 100 with either a Severne Blade 6.7 or a Hot Sail Maui Superfreak 7.0 m2 sail. Anything larger than that is killing the wave board manoeuvrability on this Evo.
2) For true wave/freewave riding in light wind, the Kode 103 with a Superfreak 7.0 m2 sail will fit the bill nicely.
3) For freemove/freeriding in small waves, the Kode 113 with a Superfreak 8.0 sail or a Kode 123 with a Superfreak 9.0 sail might be worth considering.
Option 1 is a 100% dedicated wave combo for heavyweight waverider.
Option 2 is a wave/freewave/freeride combo and you can adjust footstraps + fin setting (3 inboard and front + a wave fin; 4 outboard and back + a freewave/crossover/freeride fin) depending on what kind of programm you want to do depending on the wave & wind conditions. A true "3 boards-in-one" combo IMHO.
Option 3 is a freemove/freeride combo. Keep in mind that a 8.0 or a 9.0 wave sail is still quite big to handle when doing quick transition and manoeuver in waves...! When planing, this is still shortboarding manoeuvrability in waves as compared to what you can get while longboarding.
Your proposition of matching a Kode 113 + your current slalom sails 6.7/7.7/9.0 m2 combo is OK for freeriding or B&J, but as soon as you want to do some manoeuvers or serious ride in waves, you will be limited by these sails. You have to match the manoeuvrability of the board with that of the sail. Better take a Gator 7.0 and 8.0 m2 sail combo for freemove/freeride or a Superfreak 7.0 and 8.0 m2 sail combo for freewave/freemove program.
BTW, a Kode 113 + your slalom 9.0 sail is not an efficient match with your weight because you will be limited by a fin of 43 cm long (width OFO : 44.7 cm) which is a bit too small. This will never be as efficient as your iSonic 122 + 46 cm fin + 9.0 sail combo.
As for long board wind SUP-ing in waves, I don't have enough experience and I will leave that to other to comment.
The new concept of the SUPer Wave 8'10 looks very interresting for light wind wave riding. Freeriding is possible but the 19 cm long main fin in the thruster limits the sail size you can use on such a board (4.7-6.5 m2 according to specs) and certainly not with a full-on slalom 6.7 m2 sail...