Kant thinks that
{ 1 } - a reflective judgment is a necessary condition for there being objects of experience at all.
{ 2 } - an empirical scientist uses the idea of God in a constitutive fashion.
{ 3 } - it is obvious that Nature is the work of a divine mind.
{ 4 } - an empirical scientist must presuppose the existence of God.
{ 5 } - all scientific inquiry is guided by the assumption that nature is an intelligible unity.
See p. 352. No, he thinks that a determinant judgment is necessary for such.