Yes boosters do stack. I'm attempting to get confirmation from a dev and will update you when I do, but as of right now I'm fairly certain you can stack boosters.

Update: Ok so I have confirmed TC boosters stack, though if you get multiple of the same tc booster they will extend each other instead of stacking. So if you buy 2 100tc boosters each for a week, you’ll get 2 weeks of 100tc boosters, not one week of 200tc.