Yes, it means the leaves were carried away by the wind. It doesn't mean a strong wind or a weak wind, it just means that the wind had enough force to move them away. If we say 'the wind blew the leaves from the trees' then we would assume that it was a strong wind. If we said ' The breeze rustled the leaves in the trees' we would assume that it was a slight breeze. Blown away also has other meanings in every day English. He was blown away by her singing= He was very impressed with her singing ability. He blew him away without a second thought= He killed him without hesitation

The leaves were blown away by the wind -or- The wind blew the leaves away.