Not sure what you mean by “home to the current position” or what G29 probing in a 3 x 3 pattern will get you on a LowRider. You don’t need endstops, you just need to adjust your homing process.
3D printers rely heavily on endstops because the slicer places the workpiece within the physical envelope of the printer. With CNC routing/milling, the workpiece is placed by the operator, then the origin is set on the workpiece, and all moves from then on are (generally) relative to that assigned workpiece (rather than machine) origin.
G92 is the command used to set the current position, and is commonly used in the form “G92 X0 Y0 Z0” once the tool has been jogged to the desired zero location.