RAW it is not possible to summon both of your bonded weapons as part of the same Bonus Action. The Eldritch Knight fighter's Weapon Bond feature (PHB, p. 75) states:
Once you have bonded a weapon to yourself […] you can summon that weapon as a bonus action on your turn […] You can have up to two bonded weapons but can summon only one at a time with your bonus action.
Meanwhile the Dual Wielder feat (PHB, p. 165) says:
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 (because you've taken the necessary feat to do so), 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?
Best Answer
It will not cause balance problems
Dual wielding itself is quite weak, and the bonus you provide is minor.
It will not change game balance noticeably, dual wielding is still the weakest option from level 5.