As 45 was the second most common caliber and 9mm was much rarer in quantity, and less common, the value is different and I doubt you will find many people willing to trade.
I know Rich Daniels (Barreltester) on this site make shell-plates, but I would also expect Bruce can supply both dies and plate and get you up and running quicker than re-drilling the head.
Unless you have already got it, you will also need the small primer bar, tube, and powder spout to accommodate 9mm, as well as powder measure for your load.
When I began to load .9mm, I went with an adjustable measure until I found my ideal load and then drilled a bar to that fixed powder drop.
Good luck!.
