It is interesting that you are studying the play in the ninth grade. Many students are much older than you when they read it for the first time. The play--if you can get past the language difficulties--is timeless. It traces the minds of an ambitious and ruthless man and his wife, and what happens when the moral lines are crossed.
Of course, killing a king is a major deed. But the opportunity was there for the taking. Lady Macbeth and Macbeth knew that they would have this one opportunity to kill Duncan, and if they were able to pull such a deed off, they would have all the glory, money, power, fame that they could possibly want. The temptation was great. Think of modern day equivalents. Do you remember the Tonya Harding incident? Although no one was killed then, it did represent a breach in morality, an act had it succeeded, might have resulted in Harding winning the Olympic gold medal for skating.
But other relevant points are to be considered. If a person crosses the line and damns his soul, so to speak, what is to stop him from doing it again? And does creating an immoral act get easier every time we do it? How does our conscience deal with such deeds? The play is very interesting from a criminal mind perspective. Such shows are rampant on tv today, but not with the depth of the Shakespearean play. Keep reading; you might change your mind.
I believe that the play is supposed to make you think about (among other things) the roles of fate and ambition in determining what our lives come out like. For example, you're supposed to think about why it is that Macbeth went wrong -- what was it about him -- and what, if anything, that can tell you about how people should live their lives.
In addition, I think it keeps getting assigned because it's a certified classic -- it's been taught forever and so it keeps getting assigned sort of because it's traditional.
why is macbeth a classic tho?
Well it is boring and i must admit you have very strong points both of you , and i am acctually study the play and its hard to understand at times, esppecially the words they use, and i just don't understand it the way the teachers explain it, they make it harder :(, maybe someone could help me :)