My hard disk have a scratching noise during rendering. Is it possible to use a SSD for rendering instead of my hard disk (/home) ? Actually, my SSD is use on root partition (/).

Sure, kdenlive asks for the destination folder in the render dialog.

Just create a directory in root
sudo mkdir <yournewdirectory>

And give anyone access to it
sudo chmod 777 <yournewdirectory>

Or change the owner from root to your login user:
sudo chown <yourloginname>:users <yournewfolder>