Kant thought
{ 1 } - like Leibniz, that geometry could be proved analytically with definitions and the principle of non-contradiction.
{ 2 } - like Plato, we have intuitions of "mathematical objects."
{ 3 } - like Bertrand Russell, that mathematics is analytic and reducible to logic.
{ 4 } - the axioms of geometry gave insight into the nature of time.
{ 5 } - the a priori character of mathematics proved his theory of space and time.
No, he did not think this, and it is not clear that Plato thought it either.