The Apple Watch Series 9 features a new chip, the S9
https://techcrunch.com/2023/09/12/the-apple-watch-series-9-features-a-new-chip-the-s9/
Apple today announced the next generation of Apple Watch, the Apple Watch Series 9, which features a new processor — the S9 — that substantially boosts the performance of the Apple Watch compared to the previous several generations.
The S9 packs a CPU that has 5.6 billion transistors — 60% more than the S8, the S9’s four-year-old predecessor — and a GPU that’s 30% faster. The chip’s reportedly built on the same tech as Apple’s A15 Bionic chip, which debuted in the iPhone 13 and delivers up to 18 hours of battery life.