My cat is stinky and destructive?

I have two cats, one male and one female. Ive had my female cat for about 7yrs..and just last year i had gotten a kitten which is the boy. Hes a great cat-very lovable etc..BUT his poop stinks really bad! we keep 1 litter box in our small laundry room so both cats share which equals LOTS of poop! i have no problem really with the smell 'cause i guess im "used to it" but everyone (my mom, aunts, moms fiance) complain about the smell. And on top of THAT my cat is really destructive! On Christmas, we had a small christmas tree and he would constantly bite the fake leaves and break ornaments and such..he doesn't seem to listen-no matter how many times we yell "NO!" or spray him( he seems to like water) *shrugs* -hes very energetic but i ume this is because hes a kitten-i think he just turned a year now but anyways..my mom and her fiance but mainly her fiance want to get rid of MY cat because of those little flaws plus we are moving into a new house which is my moms fiance's so it has to be "neat" or cat free..is there any way i can keep my cat from being bad at least by a little bit, and reduce the smell in the litter box? I really love my cats to death, and i want to keep them, so id appreciate advice on what i should do so i can keep my cat.