Paraphrase. Don't shorten.
Nine is a troubled kid who was bullied for years without a Sonic to protect him. While he is capable of good actions, he's not exactly the most trustworthy due to having his own agenda (essentially living in an "idealistic safe space"). He is bitter and jaded, perhaps even more so than the other residents of New Yoke due to being an outcast for years, far more self-isolating and aggressive than his alternate universe counterpart, willing to resort to violence whenever feeling threatened, and has an exceptionally dry wit.
The defining trait of Nine's personality seems focused around the part of Tails who likes to work alone in his lab. While the original Tails can be shy of strangers, Nine has been condensed into somebody who is often introverted and shies away from any physical contact. Due to growing up alone, Nine believes that if he doesn't look out for himself, nobody will, and can be quite opportunistic.
That's not to say there's nothing of Tails left, when Sonic saved his life and gave him his friendship, Nine gradually opens up and genuinely values his well-being and opinion of him. He even comes back to help fight the Chaos Council beside Sonic and the Resistance and stays to help them win the battle.
Though he's lost Tails' youthful happiness, Nine still has his bravery, as he not only sasses Sonic repeatedly and does not hesitate to take part in battle, but even talks right back to the Chaos Council while they have him prisoner.
When Sonic tries to project his idea of Tails onto Nine, this breaks his trust in Sonic. As a result of this, Nine has become much more bitter, believing that the only person he can trust is himself, realizing that not even his only "friend" could be trusted.
Nine is a troubled individual who suffered from years of bullying without the support of Sonic. Despite having the capacity for good deeds, he is not particularly reliable due to having his own personal agenda and living in an "idealistic safe space." Being an outcast for a long time has made him bitter and cynical, causing him to isolate himself and react aggressively, resorting to violence when he feels threatened. He also possesses a dry sense of humor.
One prominent aspect of Nine's personality is his likeness to the part of Tails that enjoys working alone in the lab. While the original Tails may be reserved around strangers, Nine has become someone who tends to be introverted and avoids physical contact. Growing up in solitude has led Nine to believe that he must prioritize his own well-being because no one else will, resulting in his opportunistic nature.
However, despite these traits, Nine still retains elements of Tails. After Sonic saves his life and becomes his friend, Nine gradually opens up and genuinely values Sonic's opinion of him and cares for his well-being. He even joins forces with Sonic and the Resistance to fight against the Chaos Council, ultimately helping them win the battle.
Although Nine has lost the youthful happiness that Tails exudes, he still possesses bravery. He frequently challenges Sonic with his sarcastic remarks, participates in battles without hesitation, and confronts the Chaos Council boldly while being held captive.
When Sonic tries to impose his perception of Tails onto Nine, it shatters his trust in Sonic. Consequently, he becomes more embittered, believing that he can only rely on himself. He realizes that even his only "friend" cannot be trusted.
Nine is a troubled individual who has endured years of bullying and lacked the protection of a figure like Sonic. Although capable of kind acts, he is not entirely reliable due to having his own hidden agenda and seeking refuge in an "idealistic safe space." Years of being an outcast have made him resentful and cynical, even more so than the other residents of New Yoke. He isolates himself and exhibits aggression, resorting to violence when he feels threatened, all while displaying a dry sense of humor.
The dominant characteristic of Nine's personality reflects the part of Tails who prefers working alone in his lab. While the original Tails can be shy around strangers, Nine has become even more introverted, avoiding physical contact. Growing up in loneliness has ingrained in him the belief that if he doesn't take care of himself, no one else will, leading him to act opportunistically.
However, despite these traits, Nine still holds remnants of Tails' personality. When Sonic saves his life and becomes his friend, Nine gradually opens up, cherishing Sonic's well-being and valuing his opinion of him. He even returns to assist in the battle against the Chaos Council alongside Sonic and the Resistance, staying until they achieve victory.
Although Nine has lost Tails' youthful joy, he has retained his courage. He not only repeatedly challenges Sonic with his witty remarks but also willingly engages in battle. He even confronts the Chaos Council confidently despite being their captive.
However, when Sonic tries to impose his perception of Tails onto Nine, it shatters his trust in Sonic. Consequently, Nine becomes even more bitter, convinced that the only person he can rely on is himself, realizing that he cannot trust even his only "friend."