MMR is short for matchmaking rank. It’s a numerical value that determines your rank in League of Legends. Depending on your skill, it can be higher or lower. Furthermore, players themselves are responsible for determining which MMR belongs in what division.
L9, or fully Low Nine is an EU west club of high-ranked players known for their exceptional gameplay, but also their toxicity.
There are programs that make the game easier and allow you to rank up more easily than you normally would. The most popular way to “get better” easily and practically instantly are scripts.
Nowadays, more and more people are smurfing and honing their skills on their alternate accounts. They’re more known as LoL smurf account.