My favorite thing about minecraft is redstone. It actually teaches real life electrical logic systems. Kids get to learn these skills in an environment they care about. Many mods aim to do the same thing. Teaching engineering and other types of electrical logic systems, why not teach kids about money?
The mod works like this. VIllages can spawn a new building and NPC; A bank and banker. The banker will buy any item in the game in return for "Credit." Nearby there is a magic ledger. The ledger shows the players available "Credit" and their "Assets" and a "Search" box to find and purchase stocks. It could be coded so that the Banker can answer questions about stocks by connecting him to google's search engine. He can generate books which are generated by online articles and can be read by the player in game to learn about any stock. The player would search something like "Apples Stock Predictions" and the Banker would allow them to choose the top three articles and generate a book to give the player to read. The banker could also generate books that follow along with sites like investopedia where they have many sources to teach investing. The player could then use their credit to purchase other rare ingame stuff.
I could see this being underpowered in a game like minecraft where players don't wanna wait forever for their credit to grow at 12% for them to get anything in return. To incentivize this more maybe we'd make the dividends pay out higher in the game. Another thing we could do is making it so that it actually doesn't follow the stock market exactly. A stock's price in this game would initially follow its real life price. However when purchased the daily change is multiplied. If we made it a 5x multiplication, then say the stock grows 4% the next day, we'd make the game say 20%. This would make each stock a greater risk, however also provide a greater reward if they do buy their stock at a good time. Players would have to trade more frequently with this mod, which would fit Minecraft's time better.