However, I don’t want to to be thinking about it, or worse yet, having to come up with a replacement pin, if one should happen to fall out.
The dynamics of the mechanism favor the pin backing out of its holder in only one direction.
In the photo, below, that would be to the right, as the circled pin is shown.
This is because there is more friction between the kickstand axle and the pin when the kickstand spring pushed the kickstand into the extended position.
I don’t think the pin would ever fall out because once it get to the position in the picture, it is no longer in contact with, or acted upon, by the kickstand axle.
A few elegant fixed have been suggested.
My idea was not to put glue or thread lock on the plastic (@johnskepler is right about LSE plastic adhesion), but to put a drop of thread lock on the metal pin, to which it should adhere just fine. This would keep the pin from sliding back in its holder.
Doing this would give me a little peace of mind about the whole thing.
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Oh, and occasionally remove the spring box for a look-see.