Hi C., I'm laughing reading this. Its been a little over a year since I was in your shoes. I had so many frustrated days over the dog food being dumped into the water bowl, spilled things, destroyed things...I read in a parent magazine that babies by 9 months could usually utter mama, dada, and no. I was shocked so me and my husband decided we wouldn't say no. We said "not for babies," "boys who throw toys don't get to play," and no sounding sounds. Sounds stupid at first, but it was easier than saying no 100 times a day.
Shortly after we started 1 minute time outs. I would give a warning (would you like to put that down or would you like a timeout?) If the behavior kept up I would simply say your on 1 minute timeout for not listening. (NOT FOR WHATEVER THE BEHAVIOR WAS!!!) This is key to reinforcing positive behavior. I would sit with my son, any spot of floor works well, who seemed slightly confused at first, while on timeout for his minute. When it was up I would say you have to listen to mommy and daddy. Say sorry mommy. (Of course he couldn't say it, but trust me it sticks!)
Now my son is 27 months and has fantastic behavior. Babies are so much smarter than what we give them credit for. By 15-16 months he could sign "sorry, mommy" and by 2 years we rarely had to give daily timeouts. My son listens VERY well! Usually if I see negative behavior I stop and ask him, "Would you like to stop hitting the tv with your drum stick, or would you like a time out?" He gets the hint and we can usually avoid the timeout completely. Whatever you choose you have to be dilligent. We wanted to focus on him listening to us not the bad behavior. I am really glad I was consistant and didn't give up. We also taught him some basic signs for things, more, milk, cracker, food, sorry, mom, dad, ect..which really eased the frustration on figuring out what he wanted, and lessened the terrible twos. Good Luck, email me if you want more info. S.