I have an idea for an adventure for a group of high-ranking, experienced acolytes.
A planetary governor has announced that he would be doing the unthinkable. Granting pardons to rogue psykers! He put out a planet-wide proclamation, that any rogue psykers or untainted heretics would be granted a pardon of any crimes and be given asylum from the black ships and from the Inquisition. What's worse, the planetary governor has the backing of an Inquisitor! A full-blown radical to say the least, but one with enough influence and power to make sure the proclamation doesn't reach off-world.
Strangely enough, his methods are showing some success. Numerous rogue psykers have come out of the woodworks and being brought to the inquisitor's specially built asylum. Rumor begin flying that something truely blessed (or cursed) must be maintained within the asylum, as those psykers who are seen moving about it display a level of control that not even a sanctioned psyker could manage.
This adventure works best if the party happens to be stationed on this planet as a forward base, away from their inquisitor. They would need to find some way of communicating off-world, then possibly lead a rebellion against the governor and the radical inquisitor by breaking into the asylum, finding out how the psykers are managing such control, and rallying the local population against the governor to attempt to overturn this abominable operation.