Any tips for degassing blended soup?
Use a vacuum pump. People who pour liquid rubber into moulds use a vacuum chamber to get the bubbles out; I've heard of people degassing wine with a vacuum pump (see these youtube videos, for example); I wouldn't know why it wouldn't work for soup.

The question is of course where you get a vacuum pump. If you're doing this in a commercial kitchen I'm sure there are channels where you can get a professional one. For the home cook (like me), one option (inspired by one of those videos) would be to pour it into a wine bottle and then use a wine saver; Vacu Vin is a well known brand. You probably won't want to fill the bottle more than half full, especially if the liquid is very thick; the bubbles in the liquid will expand a lot if you lower the pressure, and it will raise the level of the liquid.