If you declare the function like above within compositionReady event handler, the function remains local to the event handler function.
To use outside, you need to declare it like this:
this.CreateSvg = function(y1,y2,y3,y4,y5,y6,y7,y8,y9){
var sim = sym.$("Stage");
var sVg = ( '<svg height="100" width="500"> <polygon id="box1" fill="#D04E00" points="500,253.327 43.6,253.327 43.6,'+y1+' 90.128,'+y1+' 136.691,'+y3+' 183.254,'+y4+'229.783,'+y5+' 276.346,'+y6+' 322.909,'+y7+' 369.437,'+y8+' 500,'+y9+' "/>')
sim.append(sym.$(sVg).css());
}
now this function becomes an attribute to the "Stage" symbol, and now you need to call it like:
sym.CreateSvg(90,80,40,30,20,20,30,0,12)
hth,
Vivekuma