Invade with an all out war?
That just seems illogical, for a species with reliable inter-solar travel we would be no more then monkeys in a cage, sure we can throw some rocket poo at them but that is the full extent of our abilities.
If they wanted something they would just take it at arms length and probe it's anus obviously...
Maybe in an extreme case where a dying society manages to only construct one life boat and they shoot it for their most promising planet found and upon arrival they have no choice but to fend for themselves here, still an all out war is just a terrible option.
Biodiversity is probably the only thing they would really want to take, resources same as ours are plentiful through all planets so that would not make sense to come and get on our rock, more then likely they would just study our oddball planet.