RAW it is not possible to summon both of your bonded weapons as part of the same Bonus Action. As per the Dual Wielder feat:

You can draw or stow two one-handed weapons when you would normally be able to draw or stow only one.

It doesn't sound unreasonable to me to allow this, but I may be missing something unbalancing.

Would it be unbalanced to allow Eldritch Knights who have the Dual Wielder feat to summon both bonded weapons as their Bonus Action?