There's nothing i've found that indicates one way or the other, and 40k fluff is so spread out and convoluted that Who Knows.
Assuming you are the GM, simply make it the way that fits your plot best.
If you're a player wanting to do something with that concept, talk to your GM about making it that way so you can do something with the concept.
Conceptually, though, there are some barriers between the two fluff concepts -
Living Saints - are high-charisma individuals empowered by the belief of the milling hordes of humanity. They typically do not start their lives as living saints, although some are said to have had blessed existences their entire lives. While their powers are 'from the emperor', it's strongly hinted that their popular following (all that delicious psychic energy) has something pretty big to do with their ability, and it does seem to manifest most often through followers, an army, a religious cause, etc. In the Eisenhorn and Gaunt novels by Dan Abnett, the nature of Saints and some links to the charismatic, psyker Inquisitors who also have powers and nature above the norm hints that perhaps they are just avatars of humanity in the same way a warboss is the avatar of the orkish waaagh.
Sensei - are 'special children' who can use the warp invisibly and even the emperor can't see them. And they're basically jedi. And it involves the Star Child, also known as oh no, god no. And they are tools of 'the illuminati' and overall everything about them reads like the fanfic of someone with very little imaginative power.
If you wanted to use them as a single conflated concept, i'd probably rip the sensei fluff right back to it's roots and rewrite them entirely, but even then you lose all the 'hints that all isn't simplistic' that make the Living Saints such interesting, powerful characters. Overall, unless I could think of some way to make the sensei better than their existing fluff, I would not try to conflate the concepts, and i'd just use a living saint (or nascent living saint) for whatever campaign or concept I was trying to embody.