Single Arduino I/O pin driving multiple DVR8834 stepper driver boards
Looking at the datasheet, section 7.5 'Electrical Characteristics' under logic-level inputs, we can see that the highest current draw of those inputs (at 3.3V anyway) is only 20 µA.  This means that even if we put 10 of these in parallel you would only be drawing 0.2 mA.  This is well under the 40 mA that the ATmega328P can handle.

Because the IO can drive so much harder than the those inputs, I wouldn't worry too much about cross talk.  This should work fine.