no, you just need a legal way of working. Soccer is a job and to do any job in the US you need a working visa. Their are many kinds a good place to start looking is the INS which can be found on the internet.
Getting married to an American citizen.
Getting an "Application for Naturalization". === ===
Yes, just like in any sport, there are soccer players that take drugs, both legal and illegal ones.
No it does not make him a citizen, but it you may sponser him for citizenship if you wish.
Check with the laws in your state before getting married, but in most states, anyone who marries a United States citizen can become a US citizen, and thus be legal.
No it is not legal to play soccer with your arms
Getting married to a U.S. citizen will not make you a legal resident. If you are in the U.S. legally you can file to adjust your status to a legal resident. If you are in the U.S. illegally, getting married to a U.S. citizen will not help. You will need to go back to your country and apply for either a K1 fiance visa or a K3 spousal visa.
Yes, but the facilities are owned by the stadium owner and they will probably ask you to record while standing somewhere off their property.
no
If you meant "citizen" instead of "citicend", then yes, Obama is a legal US citizen.
of course it can
No. Marrying a US Citizen abroad does not guarantee you legal entry to the US