I'm pretty sure the 9.0 m2 V8 will work OK on the ST 137.
You might like this combination, and then again maybe you won't.
A more germaine question is perhaps what exactly are you trying
In my opinion, the S-Types really aren't "early planers" and going with
a 9.0 m2 V8 seems to indicate you want to get the board going in less
wind that it takes to get it "powered up".
Give it a try..... you will of course need a larger fin to work with the
Hope this helps,