Naruto might be initially confused. He trusts Tsunade, so being kidnapped by her would be completely unexpected. He would probably start by asking her why she's doing this.
Tsunade would probably be very suspicious at first. Naruto suddenly appearing from the future? It's not something that happens every day. She might think it's some kind of enemy's trick or a genjutsu.
She might be initially shocked. Given her own past traumas and her relationship with Naruto, she could be hesitant at first. But then, considering Naruto's lonely situation, she might warm up to the idea and show a more maternal side towards him.
Tsunade could be a bit flustered at first. After all, she is a tough - as - nails leader, and a hug from Naruto, who she has watched grow up, might make her feel a bit vulnerable in a good way. She might then relax and even give Naruto a pat on the back in return, showing her appreciation for the gesture.
Naruto could also become angry. He might feel betrayed by Tsunade and the village. This anger could fuel his determination to prove his innocence or worth. He could set out on a journey to become even stronger, so that one day he could return and show everyone that they were wrong to banish him. He might also start to question his own beliefs and values, which have been centered around the village and its people.
He could become determined to prove his innocence. Naruto is not one to give up easily. If he was wrongly banished, he would set out on a journey to find evidence or the real culprit to clear his name and return to the village he loves.
The other kages from different villages would also have reactions. Gaara, being Naruto's friend, would be happy for him and send a grand gift. The Raikage might be a bit surprised but would respect their decision. The Mizukage would probably see it as an interesting development in the relationships between the ninja villages. All in all, the reactions would range from shock to joy, but in the end, most would support the union.
She could be angry at first. Tsunade has always been a strong - willed leader, and Naruto leaving without proper communication might seem like a sign of disrespect to her.
Well, in some fanfictions, Tsunade might be devastated. She could go into a state of deep grief and self - blame, thinking she could have done more to prevent Naruto's death. After all, she was his Hokage and had a certain level of responsibility for him.