He was suspended three different times for three different reasons. Once he was in an unauthorized place writing some graffitti. Once it was for tardiness, and once for the baggie. [This is from memory; I believe it’s accurate but someone may have the official list, which could differ on minor details.]
Trayvon was given a pass on having many valuable pieces of women’s jewelry and a flat-head screwdriver in his backpack. The school made no attempt whatever to find out if the jewelry was stolen.