That's a safe bet. SPL at the concert is likely to be higher than what you've simulated using your stereo, particularly in the low bass range, and the miniature DPA omnis do no roll off any bottom end. Check levels at the show and reduce gain on the 9100 if necessary.
For quieter material where you require more gain than what is available from the 9100 into the line-input, switch to the mic-input of the DR2d where you can increase gain on the recorder. Safe mic-input gain range on the DR2d is settings of 67 or higher. If you experience clipping or get uncomfortably closet to clipping using the mic-input at a minimal stetting of 67, you'll need to switch back to the line-input (set between 95 and 100).
For optimal gain staging, you typically want to get most of your gain from the earliest stage of the recording chain. In this case that's the 9100. So crank that up before you crank up the DR2d.