The Tacitus reference was interesting for several reasons, while it seems like a smoking gun reference on first blush, it has problems.
1. It refers to Pilate as a procurator rather than a prefect, the former being a financial officer for a province, and the latter akin to a governor, While the archeological evidence of a corner stone dated 26-37 CE shows an inscription of Pilate quite clearly as a prefectus judaeae. If he researched and referenced this passage then why the discrepancy?
2. Christus is a title rather than a name, it was given to many especially in rebellious Judea.
3. The reference appears to speak second hand and mockingly about the particular religious faction's beliefs.
While from the passage you can clearly establish that there were Christians in the second century,and that they were not thought well of by the Romans It is not a direct affirmation of the story but rather tangential as well as being not contemporary. Not exactly strong evidence of the historicity of jesus.