Yes, Bettas have been known to be jumpers, which is why it's always good to take precautionary measures to ensure that they do not jump out of your aquarium when you aren't looking. Good luck with finding a hood or with making one.. just be careful, because there's a reason as to why many folks keep Bettas in tanks, vases and bowls that are left open. In fact, most people think of a
betta fish tank as a vase or an open gold fish bowls. Bettas need to have access to the surface in order to breathe properly. They have special respiratory organs on the top of their heads.
As for adding shrimp.. I'm curious to find out how it works out. We've had shrimp and bettas before, but never together. Good luck with everything!!!