I should point out that my vested interest in this is minimal. I'm not a christian, I don't believe in god, and I think the bible is 99% made up. I don't buy the astrological interpretation because it invokes too much planning and attention to detail in a book that was very evidently an ad hoc cobbled-together anthology of mostly unrelated fantasies.
Whether Jesus existed or not is of little consequence to me ultimately, though I suspect there was someone whom he was loosely based upon, simply because it would have made no sense to invent the fictional and completely unrealistic Bethlehem census story when it would have been far easier narratively to have his parents live there from the get-go, unless there was already a guy who was known (or at least strongly believed) to have lived somewhere else. Whether that place was Nazareth or the general Galilee area is of little consequence really. For whatever reason, the writers clearly believed that Jesus had lived somewhere other than Bethlehem and went to great pains to have him be born there so as to fulfil OT prophecy.
Whether or not the character was based on a person or not however, the astrological connection is fanciful pattern-seeking that borders on sophistry. The writers of the bible were just not clever enough for that, and biblical allegories tended to be either vague or otherwise based on more fantastical numerology such as the coded language of the apocalyptic texts, rather than the stars.
Also, what would be the point? Who would the astrological symbolism have been aimed at? Very few people would have been able to decode it, if they'd even known they had to in the first place, and what would they have gained anyway? Why cloak esoteric astrology with no real message in such vague imagery? It would just be pointless.