Given the observations from our own solar system, where most planets have moons of some sort, it seems that exoplanets would also be very likely to have some sorts of moons.
In our own system, we are even finding asteroids with smaller asteroids orbiting them, and one (so far) of those smaller orbiting asteroids itself seems to be made of 2 pieces actually touching each other.
So, I think the only real question is whether we will find planets with moons that have some beneficial effects for the probability of life on the planet they orbit, or maybe life on the moon orbiting the exoplanet.
Considering the necessary relationships for that, I don't think we could yet detect that type of planet/moon system. But, I expect we will whenever we develop the ability to find them.
To me, the more intriguing question is whether we will find "double planets" that we see so often in fiction. Even double planets that are not likely to sustain life would be interesting. Can they really form and persist/survive long enough to have a significant population our there?