I agree with johnwill. The drives don't care what angle they are mounted at. The main thing to worry about there is the the connectors are fully inserted, tight and secure.
As far as wiggling causing problems, SSDs are very light so I doubt that would ever be a problem (again, assuming the connections are fully inserted). Drive, I suppose, could be a problem, if you were using the computer in a laptop while traveling down a bumpy road, and the connector was not fully inserted or loose.
BTW, there is some debate about changing the angle of operation on "hard" drives that have been in one orientation for many years. For example, some claim if the drive sat in a flat, horizonal position for long periods of time, the spin motor's bearing might create a specific wear pattern in the bearing's channel (due to the effects of gravity). And if you move the drive to a vertical orientation, or flip it over, gravity now, pulling down at a different angle, might result in accelerated wear in those bearing channels. I suppose, in theory, this might be an issue. But i personally feel in this case, "in theory" does not jive with the real world.
Explode?

No they won't. That's a bit silly. Please read Item #2 in my post #3 above to learn what
really "might" happen if you allow the fans to spin beyond design limits.