Is it safe to charge iPad PRO 4gen with 96W MacBook charger?

Yes - but some additional explanation may be helpful…

Your Macbook Power Adapter is completely safe to use with your iPad; providing that the Power Adapter itself is healthy, it will not cause any issues whatsoever. That said, if a fault were to occur, the Power Adapter being considerably more powerful than a “standard” iPad Power Adapter, the 96W Adapter has the capacity to cause considerable damage to low-power electronics.

The Mac Power Adapter supports USB PD (Power Delivery). USB PD is an active protocol; the source (Power Adapter) and sink/load (in this case, your iPad Pro) “negotiate” and agree a common Power Profile that will determine the charging voltage that will be applied.

For non-PD compliant devices - or compliant devices that fail to negotiate a mutually supported Power Profile - the Power Adapter will only supply the standard USB 5V at a reduced current. This mechanism ensures that the higher charging voltages not supported by non-PD devices are not damaged by an over-voltage condition.

You should note that while your iPad Pro can be charged with your Mac’s 96W Power Adapter, it will not charge any faster than when using the USB-C 20W Power Adapter that was likely supplied with your iPad Pro. When charged with a USB-PD Power Adapter, the maximum iPad charging rate is limited to ~20W. When using a standard USB Power Adapter, operating at 5V, the maximum charging rate is limited to 12W (i.e., 2.4A @5V).

Where the higher-power Power Adapter does provide benefit is when being used with other USB devices via a USB-C hub. A higher-output Power Adapter provides a greater “power budget” - allowing other devices to receive power while maintaining the iPad’s maximum 20W charging rate. For example, a USB-C multiport hub may typically require 10W power, plus connected USB devices (external storage, keyboard, mouse etc) also draw additional power from the source. If the connected load exceeds the available supply, the iPad may not charge - or may charge at a substantially slower rate. In extremis, both the iPad and Power Adapter will share the connected load - and the iPad may actually discharge its battery to make-up the shortfall in available power from a connected Power Adapter.

I hope this insight proves to be helpful to - in both confirming suitably of your Mac’s Power Adapter - and gaining a better understanding of factors that will impact charging of your iPad.

Apple provide the following guidance for charging your iPad with a USB-C Power Adapter:

Charge and connect with the USB-C port on your iPad - Apple Support

Yes, it’s completely safe (although your iPad will NOT charge appreciably faster than it would from a much lower-wattage adaptor)

You iPad will only “draw” as much power from the adaptor as it can safely use.

See more here:

Charge and connect with the USB-C port on your iPad - Apple Support

Yes. Not sure exactly what the various outputs are, but it should negotiate a voltage that it can use safely. They always default to 5V first, then negotiate a higher voltage if compatible. It will never negotiate a voltage that it can't properly use. What did it come with? I'm thinking the standard 20W Apple USB-C power adapter that only has 5V and 9V.