The High Court in Glasgow heard James Ainsworth, 62, told two of his female victims: "I'm a police officer, no-one will believe you."
He pleaded guilty to seven charges of sexual abuse and one of rape, committed between 1965 and 1990 in Ayrshire and Dumfrieshire.
Ainsworth admitted the offences as a second trial against him was about to start. The first trial had to be abandoned after he was assaulted outside court.
Judge Norman Ritchie QC told Ainsworth: "I was going to sentence you to 12 years, but I'm prepared to give you a discount of a year as there was no need for the victims to testify for a second time."
Judge Ritchie also placed Ainsworth on the sex offenders' register.
Defence QC Andrew Lamb said: "Mr Ainsworth had some difficulty in coming to terms with the offences."
Advocate depute Kath Harper, prosecuting, said Ainsworth's predatory sexual behaviour began when he was 14. He started touching an eight-year-old girl's breasts and progressed to raping her once when she was between eight and nine.
The court heard Ainsworth sexually abused three other girls - one of them in the Ayrshire police house.
Ainsworth told the girl, who was six: "No-one will believe you. I am a police officer and something bad will happen to your mum."
The court heard one of Ainsworth's male victims was sexually abused from the age of five. Ainsworth would pretend to be Spiderman before sexually abusing the boy.