We use jenkins for automation for our test infrastructure. The requirement is to give users the ability to use a jenkins node for their private test or debug using private jenki
Did you have a look to this question:
How to take Jenkins master node offline using CLI?
In the 1st question, there are some CLI to make a node offline.
Maybe you can create a dedicated job on the master with one parameter (the node name). This job will call the Jenkins CLI to stop your node.