This could be translated as "leave him alone" or "stop bothering him."
## What kind of words are these ##
This is a rhetorical question. The people were expressing how amazed they were that Jesus had the authority to command demons to leave a person. This could be translated as "These are amazing words" or "His words are amazing!"
## he commands the unclean spirits with power and authority ##
"he has power and authority to command the unclean spirits"
## news about him began to spread ##
"reports about Jesus began to spread" or "people spread the news about Jesus"