No tights period. End of story.
No medical excuse, no religious excuse can alter that rule. The case play is very clear on that. The player can wear pants if he/she wishes.
3.5.6 SITUATION B:
A player, for religious reasons, may not wear shorts.
Would he/she be able to wear tights under the basketball uniform shorts, warmups
or a skirt instead of shorts? RULING: NFHS basketball uniform rules do not
require that the uniform pants be "shorts." However, undergarments or tights may
not be worn which extend below the pants, therefore wearing tights “below the
uniform shorts” would be illegal. The player could wear long pants or a skirt as
the uniform "bottom" and be in compliance. (3-4)