There may be a few reasons you're getting leading in the bore, but the most common with 9mm is either the bullet is too small to begin with, or some step in your reloading process is swaging the bullet down to a smaller diameter without you being aware of it. A .356 bullet should be OK with a typical CZ barrel, but slugging it to be sure is always a good idea. Ideally you'd want a bullet .002" to .003" larger than what your barrel slugs at, but anything larger than the bore diameter should be OK. All my CZs slugged at .355" so I use a .358" cast bullet to great effect, but I could probably get away with a .356" if I had to.
With those bullets you pulled, you need to measure them to make sure they're still the advertised diameter. If you put .356" bullets in there but they measure .355" or .354" or something, you'll know there's an issue with one of your steps in the reloading process. A scratched coating usually doesn't matter too much unless it's a huge amount of coating scraped off.
The most common places you'll get accidental swaging would be when you expand/bell the case mouth and when you apply crimp. Not enough expansion will cause the bullet to be swaged down by the case as you try to cram in in there. For 9mm you should be using a taper crimp die. If you're using the Lee Factory Crimp Die, that might be your problem right there. Many, many people have reported that the carbide ring in the Lee FCD swages bullets pretty consistently.
First thing I would do is measure those pulled bullets to make sure they're still whatever diameter they were supposed to be before you loaded them. If they are, then you may need to find a cast bullet that is a little larger. I think most of the cast bullet sellers will do custom diameters if you request it
