For slow charging and performance issues with your Xiaomi Redmi 9 Power, start by checking the charger, cable, and charging port for any issues. Ensure that you are using the correct charger for fast charging and check for software updates. Managing background apps, adjusting screen brightness, and optimizing battery settings can also help with performance and battery life. If these steps don’t resolve the issue, consider checking the battery’s health or performing a factory reset as a last resort.