Are we some kind of puppets in the hands of destiny?

I don't think we depend on our destiny, I think some things are like wrotten, but others you can choose, and your choose takes you to a new "destiny", so all is about doing the right decisions at the right time, when the "destiny" gives us the oportunity to choose. So it is not actually a complete destiny, more like a semi-destiny.

I don't think it is entirely one or the other. I think it is a comination of a few things. Fate,Gods will, luck and choices that we make.

Some things we inherit like the defects in our genes or aptitudes. Other things are determined by our environment. And then there is our responsibility to change our fate, to change our personality for the better. There are options to choose, to change and to influence our fate.