Graham Scheper has a recent video on this topic. He also believes that "Hwaet" is not an interjection, but more like Red Riding Hood's "What big eyes you have!"
https://www.youtube.com/watch?v=5gZKCPk40WI
You seem to have linked the wrong video (yours is about the meaning of the name Beowolf), the right link about Hwaet is:
https://www.youtube.com/watch?v=nMIfHNn9KGs
You seem to have linked the wrong video (yours is about the meaning of the name Beowolf), the right link about Hwaet is:
https://www.youtube.com/watch?v=nMIfHNn9KGs