To my knowledge, Michelle Obama never stated we should drink 9 instead of 8 glasses of water a day. She stated people should drink one more glass of water a day.
Only the Corporate Hugging Right Wing would jump to a conclusion that stating "drink more water" is an attack on soda. Dumb as fuck. If your only drive and perspective is more Corporate power, then you might find yourself fighting for less water talk.
This talk of, not force of water is mostly due to the high temps in the nation for whatever reason you want to believe, it's a fact, it's hot. "75 percent of the American population fall short of the 10 daily cups prescribed by the Institute of Medicine – which, in medical terms, means that most people in the U.S are functioning in a chronic state of dehydration." Raising awareness for water drinking is the job of EVERY American.
And when you find yourself fighting that "There is no proof water is good for you" you might want to step back, look at what you are saying and try to use your brain instead of being sheeple and repeating everything you hear from For Profit media.