This service law ...9.1.3 some part of both feet of the server and receiver must remain in contact with the surface of the court in a stationary position from the start of the service until the service is delivered (Law 9.6); Does this mean for example that you can't be on your toes to receive and "pulse" (shift your weight down ready to move forward or back) before contact with the shuttle is made?
If, when you are shifting your weight, a portion of both shoes remain stationary on the ground, you are ok. Like you can stand on your toes, lower youself without taking your toes off the ground, and raise yourself up again on to your toes (but toes still in same spot). That is all ok.
It means that you must be stationary from the start of your service (forward movement of the racquet) to shuttle contact. So, if you are tip-toeing up and start the racquet swing and you step down (i.e. lower yourself) before contact, then it is illegal. It's okay for you to step down after contact has been made in order to get into position for a reply.
I thought it was all good as long as some portion of both feet remain on the same spot on the ground. Thus, I figured raising yourself and lowering yourself on your toes was ok, since your toes are technically still in the same spot as they were when you started the forward movement of the racket head.
That is correct; you can shift your weight or lean/stretch however you like, so long as as some part of both feet remains stationary until the shuttle is struck.
I wasn't sure about for the receiver. I've got a downloaded vid of Gade vs Taufik in this years all England semi where Gade got a "fault receiver" for moving too early. They showed a slow-mo, and I could have sworn he got it for just "pulsing" rather than actually lifting a foot off the ground...
Is there sound to that video? Can you hear what the commentators said? The umpire could have just made a bad call which happens.