Advices about reinstall mavericks (or install Yosemite ?

After an installation of Xcode 6.2 on my iMac12,2 running Mavericks 10.9.5 and bypassing some System alerts I did not understand at first, but launchd process relative if I remember well, I can't resolve some recurring alerts ( after each boots ) when the finder is launching (upper right icons loading time). I can see a stalled process in Activity Monitor: iTunes helper. (in red). I force it to quit ( maybe a bad idea ). I also have had this old famous -10810 error when I wanted to launch iTunes and some other applications.
What I did till now I can't believe my own stupidity (reparations and foolish actions)

• PRAM & SMC resetting using the appropriate shortkeys at boot
• Running a Safe boot without problems
• Running in Verbose mode
• Running in recovery mode & clean + check permissions ( several entries to fix (4))
• Fixing the launch services database with my beloved utility CleanMyMac3.0.2 but maybe other deletions/disabling of files I should not have do ( launch agents and/or login items; but not iTunes Helper login ! )
• Using this iMac in a long session, rummaging through the hidden system files

Is there any tool or anyone able to help me solve this erratic behavior of Maverick ( erratic but probably because of me )

Last resort that doesn't make me happy would probably be a reinstall Maverick above the existant OS. I have no sufficient space available to make a backup and the Time Capsule/machine restoration generally break numerous third party Apps.

If such a new installation of Mavericks delete the files that apps bought outside AppleStore install into the system itself or delete their preferences, licenses, etc… I will probably avoid. Or for that matter I'd rather bluntly migrate to Yosemite. What is your opinion ?

Please don't blame me about the mistakes done in a language I'm not familiar with. If you don't understand, ask me.

TIA, Alain