I suggest first getting a proper diagnosis from a child psychologst and follow their advice on how to best treat your son based on the severity of his symptoms.
DO NOT try to force your son to stop performing his compulsions because this will cause him severe anxiety and overwhelm him with obsessive thoughts. You need to understand that if your son truly has OCD (and it sounds like he does but again you need a proper diagnosis) he is performing these rituals (touching things, repeating words etc.) because he has obsessive thoughts that cause him so much anxiety that he is required to perform these actions and not performing them would result in severe overwhelming anxiety.
I was a child sufferer of OCD and from my personal experience I can say that the best thing you can do for your son is to suport him through this disease. He will probably suffer from it in some form for his entire life and you need to accept that as a parent and learn to help your son cope with his symtpoms. Forcing a child with OCD to stop perfoming his/her rituals is the WORST thing you can do. People with OCD especially children can not just stop perfoming their compulsions as doing sao results in severe anxiety and overwhelming obsessive thoughts.
Also do not let the psyhcoloigts drug your son up. Remember that many of them are there to sell drugs as this is how they pay their rent. Be aware of this and do what YOU think is best for your son based on the psychologts suggestions. Do not be afraid to get a second opinion if something doesn't sound right.