WaylongwayWho tried to interdict you? Most NPCs aren't a problem, even though in a Type-9 it's more of an effort than in any other ship.
If you want the real test accept several elite cargo transport missions and carry multiple loads of e.g. 192t biowaste at the same time. Those 700t cargo space need to be put to good use.
I bought my first T-9 today for the community goal. I had heard stories about NPC interdictions being harder to evade in a T-9, so I wanted to try it myself.