Man, I love talking about 'Naruto' lore! Kakashi Hatake is such a fascinating character, but no, he never opens the Eighth Gate in the series. The Eight Gates are a forbidden technique that pushes the user’s body beyond its limits, and while Kakashi is incredibly skilled, he’s never shown using it. Might Guy, his rival, is the one who famously opens the Eighth Gate during the Fourth Great Ninja War, which nearly costs him his life. Kakashi’s strengths lie elsewhere—his Sharingan, tactical brilliance, and Chidori techniques define him. The idea of him using the Gates feels almost out of character, given how much he values precision over brute force. It’s fun to speculate, though—imagine him combining Gates with his lightning-speed movements! But yeah, canonically, it’s a no-go.
That said, fan theories and 'what if' scenarios often explore this idea. Some alternate universe stories or games might dabble in it, but in the main series, Kakashi sticks to his signature style. It’s part of what makes him unique; he doesn’t need overwhelming power when he’s got brains and finesse. Plus, the Gates’ life-or-death stakes wouldn’t mesh well with his role as a sensei and eventual Hokage. Still, seeing Guy’s Eighth Gate moment was epic enough—Kakashi’s reaction to that fight alone was priceless.