Cutter has higher total possible cargo than T9, I personally would not recommend downscaling from a Cutter to a T9 for trading. Tried it and sold the T9 after a couple of trips.
You only get the good credits for selling Tritium in the CG station which is Fozard Port in Upaniklis and you'll likely have to haul that tritium 160LY from where there are supplies to that station.
I had that dilemma a couple of days ago.
Nothing to do with the CG, but when out Exploring in my Carrier, I have my Cutter geared for Mining Platinum Hotspots in Metallic Rings. I was wanting to purchase another Ship to offload this Platinum on return to the bubble AND THEN restock the depleted Carrier with Tritium, without having to keep swapping the modules for Cargo Racks.
My choices were another Cutter or a T9.....in the end I settled for a second Cutter, with all Racks bar a Slot 4 Shield Generator - as my Carrier would be positioned in the same System as the grunt work was being carried out in.........
.......also, I had a T9 a year or two back & ditched it after ONE run! boy was that Ship a crappy one!
I much prefer the Cutter even though it carries slightly less.