1)
What caused Pharaoh to suddenly acknowledge Hashem?
1.
Seforno: When he saw the difference between Moshe and Aharon, who produced living crocodiles, 1 and his magicians, who could only produce lifeless creatures that resembled crocodiles, he acknowledged Hashem's superiority over his magicians. 2
1
We may infer this translation from Seforno's comments to 8:11; refer to 8:11:1:1, and also to 7:26:1:1*.
2
Refer to 7:23:1.1:3 and its note.