TPS7A49: does it recommend that customer connect a 10k resister between en and Vin?

1) The enable pin is a high impedance pin, rough estimate of around 35Mohms.

2) We do not recommend a resistance in between Vin and En. If the customer is not using the enable functionality of the device, then they can tie En directly to Vin. This is actually what is done in figure 29 on page 16 showing a typical application circuit.

3) If the voltage of EN to Vin becomes greater than 0.3V there is a possibility of part failure. This is why we recommend tying them together so this won't happen. By exceeding that voltage you could force potentials across internal parts that may exceed breakdown, and will force the operation, or lack thereof, of components in ways not intended. This can lead to failure and/or destruction of the part.

This is ok to do, it will not break anything. In exceedingly rare circumstances connecting a resistor between these pins could cause a voltage drop across it significant enough to lower Ven below turn on(2.1V), but at a 100k resistor this should not ever be a concern.