My 8 Month Old Grandchild Is Sweet, Engaging And Happy.

My 8 month old grandchild is sweet, engaging and happy. However, she bounces up and down in her exersaucer or kicks her feet constantly when in her bouncy infant seat. She vocalizes a lot and responds to her name, smiles and laughs. She rocks and scoots backwards but is not fully crawling. She was frank breech and in a brace for 2 months. She may be a little behind on crawling and walking. However, neither of my children "bounced" or kicked in their infant seat like she does. My son walked at 9 months and my daughter at 10 months. I am a little concerned about hyperactivity and that she is not as advanced in motor development as mine were. Need I be?