Love for the sake of love is the higher form of devotion and is called Parabhakti. He accepts all offerings made with love. It is the love of the devotee that counts rather than any formal worship. Krishna is considered to be the eighth avatar. Ninth being Buddha and the tenth is yet to come and will be called Kalki.
Hindu teachings allow for many other Avatars.
These Avatars come with tremendous compassion and ability to give God-realisation to others. They always herald a new wave of spirituality to engulf mankind.