Can this be considered as a valid URL?
According to the spec * is considered as a reserved character.
Can this be considered as a valid URL?
According to the spec * is considered as a reserved character.
Technically, yes. As you mentioned it's a reservered character, but whether you should or not is the question. As mentioned in this answer:
Even though your URL scheme seems user-friendly to you, few will think to try it, and it's likely to give unpredictable results because the meaning of wildcards in URLs is hard to discern.