"Kicking the ball" is far from being a safe condition to make an educated guess.
E.g. whether the kicked ball curls to the right or to the left also depends on which part of the foot you kick it with, i.e. the initial rotation. Another example is a golf ball. Players can play hooks to both sides, independent of whether they are right or left handed.
The curl itself depends on the ball's surface, which isn't smooth. Especially the joints play a crucial role, because they cause tiny turbulences which in return cause differences in air resistance on each side of the ball, which at last causes the curl.
So my favorite explanation is: Without additional information on the starting conditions, it's primary the joints and secondary the surface structure, which are typically both different on a football and a netball. Also think about the fact, that American football "balls" have joints along the direction it is thrown. This also explains, why extra points or long distance kicks aren't as easy as one might think.