Only 9 out of the 10 are Moral Laws. There are other Moral Laws besides the 9 out of the 10, too. The Sabbath is not a Moral Law, it is a ceremonial law. A Moral Law is any Law that a person on instinct knows to do as a part of doing good (of which is a part of nature). The Gentiles by nature keep the Law without having the Law (Romans 2:14). This would be the Moral Law.
Nowhere is the Sabbath command repeated as a command in the New Covenant by either Jesus or His followers. In fact, Colossians 2:14, and Colossians 2:16-17 says that we are not to allow others to judge us on whether or not we keep the Sabbaths, dietary laws, etc. (For they are merely a shadow that is cast by the body of Christ). Paul says, "Christ is become of no effect unto you, whosoever of you are justified by the law; ye are fallen from grace." (Galatians 5:4). Acts of the Apostles 13:39 says we cannot be justified by the Law of Moses.
"And by him all that believe are justified from all things, from which ye could not be justified by the law of Moses." (Acts of the Apostles 13:39) (KJV).
Granted, I am not advocating disobedience to God's commands after one is saved by God's grace through faith in Christ. I believe we must obey God's commands as a part of salvation. But these would be the commands that come from Jesus and His followers, and not the commands of Moses. For the Law came by Moses, and grace and truth came by Jesus Christ (John 1:17). Jesus told us if we will enter into life, keep the commandments. Jesus mentioned the Moral Law when asked which ones we are to keep (See: Matthew 19:17-19).
Side Note:
Again, I want to stress that before a person can obey God's commands in the New Testament, they need to first be saved by God's grace through faith by asking Jesus to be their Savior (Romans 10:13), and by seeking forgiveness of their sins with Him (Luke 18:9-14), and by believing in His death, burial, and resurrection on their behalf for salvation (1 Corinthians 15:1-4).