I thought your posts were wobbling because they weren't set yet (as no hole was dug yet). If they are wobbling after they are in the holes, you may need to pull them out and try again (not in the exact same spot). Either or both deeper or with more attention to the tamping (put a little soil in, pound it down. put a little more in, over and over). It is easier to tamp it solidly if the hole is just a little bigger than the post.