TORONTO -- A nine-year prison sentence for a day-care supervisor who used the toddlers he was looking after to make child pornography is enough to both denounce his behaviour and act as a deterrent to others, the Ontario Court of Appeal ruled on Wednesday.

In upholding the sentence, the court rejected the prosecution's request to up the man's sentence to 15 years behind bars.

"The message the nine-year sentence sent is loud and clear," Justice Robert Sharpe wrote for the appeal panel. "I am not persuaded that the longer sentence sought by the Crown at trial and on appeal would appreciably add to the deterrent effect of the sentence that was imposed."

In fact, Sharpe said, a longer sentence could discourage guilty pleas and undermine the idea of rehabilitation.

Court documents show police in Peel Region west of Toronto searched the man's home and found a "massive amount of graphic and highly disturbing" images and videos of girls aged two to three years old.

The man, 39, identified only as S.C., pleaded guilty to eight counts of sexual assault, eight counts of making child pornography, and one of possession of child pornography. He admitted to exposing the children's genitals while they napped and taking close-up photographs with his phone.

While the prosecution argued a sentence of 17 to 19 years would have been appropriate, it recommended a 15-year term. S.C., who lived with his mother and had worked at several daycare centres as an early childhood educator, asked for six years.

In March 2018, Ontario court Judge Donald McLeod sentenced the first-time offender to a total of nine years in prison -- six for the sexual assaults, one for making child pornography, and two years for possession of the obscene material. McLeod noted the impact S.C. had on the victims' parents, who gave pre-sentencing statements to the court.

"A common theme that resonated through the various messages was real and palpable -- emotional destruction of trust," McLeod said. "The statements were riddled with emotional moments that run the gamut from self-doubt and guilt to anger, and feelings of betrayal."

On appeal, the prosecution said the nine-year term was far too lenient.

Among other things, it argued McLeod paid too much attention to mitigating factors, such as S.C.'s guilty plea and the lack of brutality. The Crown also said the judge had run afoul of legal provisions enacted in the Criminal Code in 2015 that stiffened punishment for those who prey sexually on children.

The Appeal Court disagreed, saying McLeod was aware of the provisions and properly tailored the sentence to the overall seriousness of the crime.

"There can be no question that these were very serious offences that called for a substantial prison sentence," the Appeal Court said. "(But) the trial judge's reasons indicate proper awareness of both the gravity of the crimes for which the appellant was being sentenced and the legal principles bearing upon the appropriate sentence."