  Observed active galactic nuclei at redshifts $\gtrsim 6$ suggest that
supermassive black holes (SMBHs) had formed early on. Accretion of matter onto
remnants of Population III stars leading to SMBHs is a very slow process, and
therefore, such models encounter difficulties in explaining quasars detected at
$ z \gtrsim 6$. In this paper, we invoke collapse of dark bosonic halo matter,
existing initially in self-gravitating Bose-Einstein condensate (BEC) phase, to
lead to formation of SMBH. Making use of Gross-Pitaevskii equation and
employing a Gaussian trial wavefunction, we determine the time dependence of
its parameters and thereby, track the time evolution of the wavefunction. If
the condensate, made up of identical dark bosons of mass $m$, collapses to form
a black hole of mass $M_{eff}$ as soon as the former's effective size shrinks
below the corresponding Schwarzschild radius, a simple inequality $ m \ M_{eff}
\gtrsim 0.64 \ m^2_{Pl} $ can be derived, that ensues from a competition
between attractive self-gravity and quantum repulsion arising due to
uncertainty principle. We show that formation of SMBHs takes place on dynamical
time scales $\sim 10^8$ yrs. Existence of ultra-light ($m \sim 10^{-23} \
\mbox{eV}$) dark bosons not only can lead to SMBHs of mass $\sim 10^{12} \
M_\odot$ at $ z > 6$ but also such particles can masquerade both as dark matter
as well as dark energy. Discovery of aligned radio-jets in the ELAIS-N1 GMRT
deep field leads us to make simple estimates to demonstrate that vortices of a
rotating BEC that collapse to form black holes can give rise to SMBHs with
aligned spins on scales exceeding cluster size length scales, each with angular
momentum $J \lesssim 3.6 \ n_W \frac {G M^2} {c}$, where $n_W$ and $M$ are the
winding number and mass of a vortex, respectively.
