Doubt he has the 160million to buy and outfit a Python and it cuts his cargo hauling abilities down over 60%. Bad move.
Inexpensive? lolcopter. And again, he'd only be able to haul a 3rd of what he is able to now. Bad move. If he doesn't have the money to a rate his T9, he damn sure can't a rate a Python.
Type-9 Base Cost: 73 million
Python Base Cost: 55 million
Anaconda Base Cost: 141 million
Yes, inexpensive, relatively speaking.
The thing with PVP interdictions is they behave nothing like NPC interdictions. Also not really a great idea telling someone to downgrade ships, OP just needs to learn to defend himself, it isn't exactly hard, just takes a little practice and more importantly discipline, it is easy to just start mashing buttons and trying to run when all hell is breaking lose.. All it takes is to remain calm and follow a procedure, no need to downgrade cargo space and switch to a Python or Anaconda.
Pretty sure if you can beat a PVP interdiction you can beat the best NPC interdiction. Yes, Players aren't going to generally make stupid interdictions, like attempting an interdiction in the cone of a white dwarf that insures their destruction - NPC's will. Nor will players interdict someone into the corona of a star or at orbital entry of a planet, causing interdiction to break automatically. NPC's will though.
NPC's tend to be rather patterned and predictable, Players on the other hand... not so much.
And we don't know what the OP's actual cargo capacity is - granted with a Type-9 it IS pretty easy to break 200 tons without much thought. However, being an admitted New Pilot, and considering swapping ships at this point already, it seems more reasonable to make a smarter, somewhat lateral move to a more multi-role suited ship that is vastly less expensive than an Anaconda, far easier to get accustomed to flying - the Anaconda's high rear bridge and unusual view can make it quite challenging for the inexperienced pilot, and even a bit awkward for experienced pilots (I still bump my head once in a while undocking mine).
But that is one of the nice things about Elite - we can all be right and we can all be wrong at the same time. The real question here is, what is a better fit for the OP? Only (s)he can answer that.