Genetic Mutation- (genetics) any event that changes genetic structure; any alteration in the inherited nucleic acid sequence of the genotype of an organism
Genetic Disorder- genetic disorder
n. A pathological condition caused by an absent or defective gene or by a chromosomal aberration. Also called hereditary disease, inherited disorder.
Source: Dictionary.com
Morphs are mutations, no doubt, but I would be hesitant to call it a disorder. As stated above, disorders are usually detrimental to the animal or "pathological", which is usually disease.
As of now Spider don't do anything that normal balls don't do, besides a little wobble. If it doesn't affect the life span, feeding, breeding habits, then to me it is not a disorder yet. We also havn't been keeping spiders long enough to determine if that is the case or not.