is it okay to gaming on my iPad 9th generation while charging?

Your iPad will suffer no harm in being used while charging, or being connected to external power for extended periods - whether in use or not. This usage model is common in Point of Sale and Kiosk applications. The iPad will optimally charge your iPad battery, modifying its charging strategy as appropriate.

More information about iPad’s battery management can be found here:

About iPad and iPhone Charge Management Feature – Apple Support

You’re very welcome.

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