Neither you need a chat bot, in order to do it without permission from the streamer.
A pubsub client for if you want to go pubsub with permissions.
A webhook reciever for if you want to go eventsub with permissions.
But I’m not sure why a streamer would grant you permission to read bits events, if you are only collecting it for statistical purposes and not doing something with the events in the game.
See also section VI. Data Policy in the Developer Agreement
A Twitch Extension, the bits would be used in the extension not as a result of the game being streamed. And the bits usage would have to do something in the extension (that extension could then trigger something in the game, Minecraft use bits to spawn a creeper on the player or something like that for example), they generally can’t be a “flat donation”. Which is what is done in chat (essentially). And sure a bits usage in chat could do something “meaningful” in game as well.
See also the Bits AUP