The maximum number of $90^{\circ }$ angles between bond pair of electrons is observed in:

$s{p}^3{d}^2$ hybridization leads to an octahedral geometry. In an octahedron, all bond angles between adjacent bonds are $90^{\circ }$. There are $12$ such $90^{\circ }$ angles in an octahedron, which is higher than in trigonal bipyramidal ($ds{p}^3/s{p}^{3}d$) or square planar ($ds{p}^2$) geometries.