The first time I flew with stoma supplies the border force had no hesitation in confiscating my 'special' scissors, despite my protests. if I had known this was going to happen , I would have either left them at home or put them in my main luggage. After that, I had my wafer holes cut to size. However, if your stoma changes then that poses a problem.
Alternatively, after that incident I started thinking of something other than scissors to cut the holes and came up with the concept of 'pastry cutters'. these would probably be okay for a temporary solution but they are usually fixed sizes in a set. I then thought I would try my hole-cutting tool attachment for my hand drill. ( it only worked with a jig to hold the wafer in place) so was too fiddly to be practical. However, in my shed, I found an old-style cheap hole cutting tool which had a whole set of interchangeable hole saws. I took the ones that were closest in size to my stoma and ground the saw-edge off until it became a sharpened blade. This worked well for cutting holes and all it needed was hand pressure (although at first I did use a hammer!).
As I see it, the beauty of this cheap DIY system is that there are a range of hole borers that fit in the same device, so if your stoma changes size or shape you would have the option of changing the cutter.
Having put in all the DIY work to make something suitable for myself, I then saw that one of the manufacturers of stoma gear were offering what sounded like the same sort of hole-cutting gadget. I'm sorry, but it was a long time ago and I cannot now recall which company it was. I have found that the larger manufacturers have R&D departments where they experiment with new ideas, so if you contact a few of them, they might have such a device in their store.
The hole boring device is not pointed, like the scissors, so is unlikely to be viewed as a 'threat' by border patrol.
I hope this information is helpful.