He was a head of year seven at Ravens Wood School, in Bromley, when arrested in February. None of the charges relate to a child at the school.
Computer equipment taken from his home showed he had recorded online abuse.
Detective Sergeant David Shipley, of Kent Police's Public Protection Unit, said: "Wells was in contact with a number of vulnerable children, for his own sexual gratification.
"He went further than online offending, and met with a very vulnerable and young child, where serious sexual offences took place.
"This case is an example of how online behaviour can change to real world abuse, and should highlight the dangers of child exploitation online and that these are real children with real lives that are damaged."
Following a search police discovered evidence showing Wells had downloaded child abuse images and videos.
He also admitted talking to children online using a webcam and engaging in sexual activity, which he recorded, and that he had travelled to Berkshire where he met a boy and abused him.
A spokeswoman for Bromley Council said "normal safeguarding procedures" were followed as soon as police informed Ravens Wood School that an investigation was under way.
She said: "Mr Wells was suspended immediately and he subsequently resigned from his post.
"The school's own investigation and that of the police found no evidence whatsoever of any wrongdoing connected with the school, its pupils, staff or equipment."
Wells was also made subject to a Sex Offences Prevention Order for 20 years, which will control the access he has to both children and the internet.