The 9 may stabilize the 75 gr Scirocco's. Around 23gr Varget was where my SL-8's sweet spot was/is....~ 2XXX fps....I have 8 twist(Edit,,,,I think the FPS is a typo in my notes.... I was working up loads but it the number quoted earlier was too hot a load. I think 2650-2700 fps is more accurate after I backed down.)
Good BC for caliber, but I do not recall it off the top of my head and it is not in my notes.
I have wrestled with Scirocco's in other calibers but the 223 seems easy to load for and they are a great hunting bullet. FOR VARMINTS