Game over!
Thanks to those of you who have partecipated. 
Here are the correct answers.
“I am Bobbin. Are you my mother?” - At first this quote might be perceived as a dialogue line from “Loom” but actually it’s from “The Secret of Monkey Island”. It’s something that Guybrush says after he is fired out of the Fettuccini Brothers cannon.
“How much wood could a woodchuck chuck if a woodchuck could chuck wood?” is from “Monkey Island 2: LeChuck’s Revenge”. Guybrush asks this question to the carpenter. In Thimbleweed Park there is a similar line, but it says “How much wood would a woodchuck…”.
“I’m not putting my lips on that.” is from “Full Throttle”. It’s the standard reply for the mouth icon/action.
“You couldn’t find a sale at yacht club!” is from “Grim Fandango”. Manny Calavera is a seller and his boss, Don Copal, tells Manny that he isn’t able to find good clients.
“He hasn’t been at dinner for 5 years.” is from “Maniac Mansion”. Ed is worried for his father.
“You have kept yourself Karmically clean” is from Zak McKracken. It’s something that Swami Holanwanda tells to Zak.
“I am sorry to do this to you little fella, but it’s for the future of the whole planet.” is from “Day of the Tentacle”. Bernard tells it when he hibernates the hamster.
“Good thing my life expectancy is only six years.” is from “Sam & Max hit the road”.
“Toto, I don’t think we are in Kansas anymore.” is from “The Dig”, when Boston Low realizes that the protagonists have been transferred to an alien place. No, it’s not from the textual/graphic adventure about the Wizard of Oz, I’ve checked it.
If you think that I’ve made mistakes, feel free to correct them but be aware that it’s improbable that it will change who the winner is. 
And the winner is…
CLICK HERE to reveal the WINNER!
@Caven got a 7/9 score, congratulations!
Those who ranked #2 guessed correctly 5/9 quotes.
Caven wins two DVDs generously given away by Someone.
I hope that you enjoyed this little game. Similar community games are quite common on other adventure game forums. Maybe we can make them an habit, if there is enough interest.