I would cut nothing until late winter. When you do cut, after making your cuts, wipe down your tools with 70% ethanol to kill any pathogens that might have adhered to the cutting surfaces. Wash hands after handling this tree before touching other maples. If possible spatially separate this tree from other maples by some distance, keep this maple downwind of the rest of your collection, never upwind. You want to avoid this disease spreading. If it is anthracnose, it is spread by splashing of water drops. So this tree should never be above any of your other maples where water can drip down from this tree. But if it is not anthracnose, it might be airborne, hence the need for spatial separation. This is "proper disease control" where the focus is to prevent spread.
Myself, I would compost the tree and not re-use the soil. Sterilize the pot by an alcohol, or a 10:1 water : household (laundry) bleach solution. The bleach (calcium hypochlorite) solution needs to be diluted to get best sterilizing activity. Rinse empty pot in this before re-using pot. This rinsing of pots in bleach is a good "standard practice" for good plant hygiene if one wants to control easily transmitted plant pathogens and plant virus.
