I have seen 'combat' builds and I have fitted turreted pulse lasers to mine but I haven't figured out how to get them to fire on anything yet
I have been interdicted about 4 times so far by npcs and only once gave me any problems. I had a go at playing the mini game and was doing very well until I suddenly lost. Waiting for my fsd to come back while being attacked by 2 clippers meant that my shields were stripped and hull down to 47% when I escaped. Although my interdiction response isn't as smooth and efficient as it used to be as I have got rusty.
Against npcs the T9 feels quite survivable so far and gives me 1.8 million a trip. Since buying it I have made 50 million so another 25 and it will have paid for itself.