If we're talking only about WW2, simple search gives us:
Germany: G7e T4, T5, T10 and T11. Serious experiments on homing torpedoes began in 1936.
US: Marks 21, 22, 24, 27, 28
(some of the torps listed above aren't submarine launched).
Gameplay period, though, is not only WW2, and later everyone got hands on that technology.
At this stage of the development it's too early to talk about how much homing will exactly take place it may as well be some course corrections, but what certainly isn't likely is toprs turning around and chasing you across the map. And even after closed beta will begin everything will be subject to change, so let's be calm right now, and see for ourseleves.