I plan on using my old Line 6 AM-4 amp modeler for my next gig. I usually just use single pedals, but after experimenting with the AM-4, I found a sound I really like.
I would like to use a Boss DD-7 Delay pedal to combine with my AM-4, now here is the catch. The delay pedal has a 9V DC adaptor and the AM-4 has a 9VAC adaptor. If I connect the pedal with the AM-4, will it damage any of the two in any way if I connect both to a power supply ?
^ Correct, they can't be daisy chained.

Plugging a DC power supply into the AM-4 will damage it, plugging an AC power supply into the DD7 will damage it.