Burying PEX Pipe in the ground
Yes, but be sure to bury it below the frost line and ensure that none of the backfill is large enough to puncture or damage the pipe.  A clean run of PEX is preferred but if you must use joints, follow the procedure from the manufacturer.
In the case of Sharkbite connectors, the manufacturer does support using them buried provided you follow their procedure:
Buried Sharkbite Connectors
I'll note that some prefer PEX crimp connectors for this application but if you don't have the tooling that can be cost prohibitive.