Logic studio 9 and OS X Yosemite

Hello,

I previously had a CD version of logic studio 9. I have tried to install it on my new mac book pro 13' retinal display which is OS X Yosemite and it is not working and I'm guessing this is because it is wanting me to update the software but i do not really want to. I can see that the quality of the logic studio 9 isn't as crisp as it should be and feel it was a waste of time using up the storage on my new mac to install it, Do you think its worth me having the old version of logic pro studio 9 on my new mac or should i buy logic pro x ?