Re: WST for 9mm ??
Patience, I'm sure somebody that knows what they're talking about will be along in a while...
That being said, I think WST might be too fast for 9mm. I use WS<span style="font-weight: bold">F</span> in 9 & 40, and it works pretty well for me, WST is a faster powder than WSF.
For .40S&W, the Hodgden site says anywhere from 4.4 - 7.8 grains of WS<span style="text-decoration: underline"><span style="font-weight: bold">F</span></span> and 3 - 5.9 grains of WS<span style="text-decoration: underline"><span style="font-weight: bold">T</span></span>, depending on bullet weight & desired velocity.
Moving down to 9mm, WS<span style="text-decoration: underline"><span style="font-weight: bold">F</span></span> is 3.7-5.7 grains. No data for WST.
Extrapolating from 40 to 9mm, the WST loads should be in the 2-4 grains range. That's really really small, and leaves very little room for error, with large possibilities of double (or more) charging without overflowing the case.
I wouldn't do it.
Stay safe!