There are few (if any) multiport adapters for Lightning.
Your iPad9 can be connected to many Lightning adapters that will individually provide connection to a single other port - such as HDMI, VGA, wired Ethernet or USB. As such, simultaneous connection to multiple external external interfaces will be difficult.
Other than accepting that you can only connect a single adapter/interface appropriate for the specific task at hand, you might consider using an Apple Lightning to USB 3 Camera Adapter:
https://store.apple.com/xc/product/MK0W2ZM/A
Don’t be fooled by the name of this adapter - as this adapter is key to connecting successfully your iPad to any other USB devices. This Adapter includes and USB Controller and Root hub. With this, you may be able to connect a self-powered USB hub, to which you may be able to connect other USB adapters (e.g., HDMI, Ethernet).