The 12 politicians and activists had all denied the charges.
Three other defendants were found guilty of disobedience and fined, but will not serve prison sentences.
Activists in Catalonia are on the streets in Catalunya.
Comments are being posted on social media, the clearest one being: "9 years in prison for two peaceful activists. This is Spain. Shame."
This verdict not only sets a dangerous precedent, limiting freedom of expression and protest in Spain, it will deepen the long-running political conflict in Catalonia, said other comments.