Mr Justice Garrett Simons granted the applications by the nine people for permission to use the material for pending or intended litigation against former INM chairman Leslie Buckley and/or the company itself.
INM had not opposed the applications.
Mr Buckley, who denies any wrongdoing, opposed the applications on several grounds.
The applications were on behalf of Sam Smyth, Vincent Crowley, former INM executive Andrew Donagher, ex-chief financial officer Donal Buggy, former head of group treasury Anne Marie Healy, former INM employee Mandy Scott, PR executives Mark Kenny and Harriet Mansergh, and by former INM solicitor Simon McAleese.
They are among a group, known as the INM 19, whose data was allegedly interrogated.
In their separate proceedings, the nine allege, among other things, breaches of data protection, privacy and of their constitutional rights.
The applications arose from the Office of the Director of Corporate Enforcement (ODCE) having secured court orders in September 2018 appointing inspectors into INM over the alleged leak and other matters.
Last year, the High Court ordered release of the material at issue to two others suing for alleged breach of privacy over the alleged leak, former INM group CEO Gavin O'Reilly and former INM executive Karl Brophy.
In a reserved judgment on Friday, Mr Justice Simons was satisfied there are "special circumstances" justifying an order that all nine are entitled to use the documents in the separate proceedings envisaged.
Materials at issue
He noted four of the nine, Ms Kilroy, Mr Mansergh, Mr Buggy and Ms Healy, had, unlike the other five, not previously been supplied with the material at issue - affidavits, with some parts redacted, and exhibits.
Those four, for reasons including their names appeared on a spreadsheet setting out the so-called INM 19, were also entitled to be given the material, he said.
In ruling all nine can use the material for their intended proceedings, he was satisfied that was in the interests of justice and did not confer any improper litigation advantage on the applicants.
The was because the content of the disputed material is already in the public domain and forms part of the court record in respect of a hearing in July 2018, he said.
Moreover, two interested parties, Mr O'Reilly and Mr Brophy have already been permitted use the documents for their claims for alleged breach of privacy, he said.
Another factor was that the parties providing the documents sought, INM and the ODCE, were not objecting to granting permission to these applicants to use the material.
INM had objected to Mr O'Reilly and Mr Brophy using the material, he noted.
In finding the order was in the interests of justice, he said the "defining feature" of the wrongdoing alleged against INM and Mr Buckley is its "covert and furtive nature".
This feature made it less likely the applicants would have been aware of the alleged wrongdoing had it not been for the disclosure of that as part of the process leading to the inspectors appointment in September 2018, he said.
Not only would it be artificial to restrain the moving parties from now relying on the material, it also has the potential to cause them an injustice, he said.
While not prejudging the outcome of their proceedings, it was a matter of record that the material which caused then High Court president Mr Justice Peter Kelly to appoint the inspectors was sufficient to persuade him there were circumstances suggestive of the company's affairs being conducted for an unlawful purpose, the judge added.