no
there is no reason
There are six year olds that play it, but it is up to the parents to decide if you can or not.
no
Yes, yes they do
Play Call of Duty.
Call of duty 2 through call of duty4...they are more cartoon based than the later versions
It all depends on his/her maturity level. I first started play Call of Duty when I was 4 or 5.
Largely, it depends on the standing of the parents on whether or not their 9 year old should play Call of Duty or not. It should also be noted that the modern Call of Duty series is rated "M" for Mature 17+. This rating is not posted on the original Call of Duty, Call of Duty 2, Call of Duty: United Offensive, or Call of Duty 3 - in which are rated "T" for Teens.
Of course,as long as the parent/guardian allows the 9 year old too.
No only people who are 20 and older should play it.
17+
Heroes 2 does not appear to be a call of duty game title, but many Call of Duty games are rated M and not T so it is really an adult game