There is almost no instruction for postures #9 through #12. I think this is because postures #1 through #6 are for unifying the jing phase and postures #7 through #12 are for the Chi phase. So 1-6 deal primarily with the blood flow to the organs and unifying them with the breath. Postures #7 through #12 are using and stabilizing the CSF.
That’s why #7 is back in the lower tan tien. You are returning to the beginning and “opening” the lower tan tien at a deeper level. Posture #8 is working the kidneys using the CSF.
I have my way of working with each of the other postures. I may be right. I may be wrong. I’d encourage you to read the descriptions in the bonus material. I think there are some interesting hints. Note that posture #9 starts playing with the connection between the palms similar to the Water Palm Change. Note that posture #11 is “integrating many different vectors” just like the Mountain Palm Change. And, note that posture #12 “integrates the energies of the organs” just as the Lake Palm Change is the integration palm change.