Some of his care home victims were said to have hid in cupboards or in dog baskets to avoid abuse.
During his trial it emerged that he kept his role despite being suspected of taking obscene photos of a child.
The siblings said they could never escape the torment of the abuse, and even struggled to cope with the memory of the “snarl on his face” as he carried out his crimes.
Kim Leslie, specialist abuse lawyer and partner at Digby Brown Solicitors, led the civil action against the Kirk on the grounds of vicarious liability.
She said: “Ian Samson was rightly jailed for abuse he inflicted upon children after exploiting his position with the Church of Scotland.
“The significant sum secured for our clients also gives you an idea of just how extreme Ian Samson was and how horrifically our clients suffered – in terms of settlements made public against religious groups, this is certainly the highest value I’m aware of in the 20 years I’ve practised law.
“Sadly, there will be other brave survivors who have fallen victim to similar campaigns of abuse and to them I would say stay strong, keep going and when you’re ready to talk or take action then there’s a wealth of support for you when the time is right.”
A Church of Scotland spokesman said: “The abuses perpetrated by Ian Samson at Lord and Lady Polworth Home in the 1970s are matters which have been examined by the criminal courts and by the Scottish Child Abuse Inquiry and for which we have expressed our deep and sincere regret.
“We became aware of the full facts in 2013 at which point we offered our full support to the victims. While Samson’s abuse of children was wider than his activity in Lord and Lady Polwarth Home, it felt important to us that there was full acknowledgment of the harm which did occur in our care at the time, and the longer term consequences for three siblings involved.
“The safety of children is of paramount importance to us, we have carried out a full independent review of the circumstances occurring in the 1970s so that we could learn any lessons for our safeguarding practices today. We did offer sight of that review to the family affected before it went for publication, through Police Scotland, however we are not aware of whether they have seen it.
“Whilst this settlement can never undo what has been done, we hope that it finally brings a sense of justice to the individuals affected and provides some small redress for the trauma which they experienced while in our care.”