Hi Willow and
to the forums!
You've been given great advice so far and I'm glad you won't be following the breeder's advice, that's definitely not a good way to earn a budgies' trust. I would hold off on giving him millet from your hand just yet because despite the fact that he's comfortable with it, right now he's just associating your hand with food so it's not truly helping him form a bond with you. Sitting by his cage and talking/reading to him is a great idea for the first week or so in order for him to begin to see you as someone he can trust. During your vacation, don't tell your partner and the pet sitter to feed him millet, tell them to sit with him next to the cage and do the same thing. He doesn't have a fear of hands so feeding him millet won't help him right now; it's the individual people that he needs to get used to. Having everyone sit with him and read/talk to him will make him feel more at home.
If you have any questions after reading through the forums' many budgie articles and stickies, be sure to ask as we'd love to help!
We look forward to meeting the little fellow soon