Insofar as it is possible to determine from information that is available, if Find My indicates the erase command is “pending”, the command has not yet been received by the target device. If not shown as “pending”, the command has been both received by the target device and acknowledged.
For the erase command to be received, the target device must have an active WiFi or Cellular network connection - or Bluetooth connection to an Apple device that is participating in Apple’s Find My Network.
As soon as an erase command is received by the target device, the target’s Secure Enclave (i.e., its security chip) is crypto-erased. This process destroys all the cryptographic keys that are required to access the encrypted filesystem - rendering all locally stored data permanently beyond reach.
Here is Apple’s advice for lost or stolen devices:
If your iPhone, iPad or iPod touch is lost or stolen – Apple Support
Use the Find My app to locate a lost or stolen device – Apple Support
If the Find My iPad feature was enabled prior to it being “misplaced”, then if active, you would stand a good chance of locating it.
However, if the feature was not activated prior to being misplaced - or the iPad has been inactive for more than 24 hours, the last known location will not be available - and the opportunity to use technical means to recover the iPad have been lost.