Hey, African Mustache!
My two cents: 9.2% is huge. Really, really huge. The finnicky part is, most years the stock market does better than that; the exception is the years where it goes much further the other way (recession, etc).
If I were you, I would find a percentage I'm happy with - 80% / 20%, or 70% / 30% - that has you devoting the majority of your assets to your mortgage, with a little bit left for investment. Then, I would re-evaluate whenever the stock market takes a significant dip or a recession comes around, until your mortgage is paid off.
For example: Shovel $1,500 of your $2,000 free cash into the mortgage this month, the $500 remaining goes into VOO. Next month, there's political turmoil impacting local stock, or the U.S. market has dropped 30% - I'm switching the percentage and putting $1,500 into the stock market to take advantage of the dip. Historienne's got a great point about the currency exchange, too. Take advantage whenever the U.S Dollar's on sale.
Good luck, and welcome to the class of 2030!