Minimal components for arm A9 dev board
I admire their enthusiasm for trying to make such a design as a school project. But you talk about DDR3 memory and that makes it far too complicated as a practical proposition. You might spend valuable time and costs on fixes, debugging and respins just to get the IC and memory working. That makes a big dent in the time to get whatever application you also had in mind working.

Of course, the project might be all about design and assembly of the electronics, with the application being irrelevant. But I think it's making a rod for your own back.

Just to follow on from your question...

There are a good many low-cost demo' boards containing an ARM-A9 and bulk RAM already. You might instead consider designing and making an expander board for one of these off-the-shelf demo' boards as the project. That would simplify the complexity and requirements on your board while keeping whatever application you'd imagined possible.