  We report CCD $V$ and $I$ time-series photometry of the globular cluster NGC
6333 (M9). The technique of difference image analysis has been used, which
enables photometric precision better than 0.05 mag for stars brighter than $V
\sim 19.0$ mag, even in the crowded central regions of the cluster. The high
photometric precision has resulted in the discovery of two new RRc stars, three
eclipsing binaries, seven long-term variables and one field RRab star behind
the cluster. A detailed identification chart and equatorial coordinates are
given for all the variable stars in the field of our images of the cluster. Our
data together with literature $V$-data obtained in 1994 and 1995 allowed us to
refine considerably the periods for all RR Lyrae stars. The nature of the new
variables is discussed. We argue that variable V12 is a cluster member and an
Anomalous Cepheid. Secular period variations, double mode pulsations and/or the
Blazhko-like modulations in some RRc variables are addressed. Through the light
curve Fourier decomposition of 12 RR Lyrae stars we have calculated a mean
metallicity of [Fe/H]$_{\rm ZW}$=$-1.70 \pm 0.01{\rm(statistical)} \pm
0.14{\rm(systematic)}$ or [Fe/H]$_{UVES}=-1.67 \pm 0.01{\rm(statistical)} \pm
0.19{\rm(systematic)}$.Absolute magnitudes, radii and masses are also estimated
for the RR Lyrae stars.
  A detailed search for SX Phe stars in the Blue Straggler region was conducted
but none were discovered. If SX Phe exist in the cluster then their amplitudes
must be smaller than the detection limit of our photometry.
  The CMD has been corrected for heavy differential reddening using the
detailed extinction map of the cluster of Alonso-Garc\'ia et al. (2012). This
has allowed us to set the mean cluster distance from two independent estimates;
from the RRab and RRc absolute magnitudes, we find $8.04\pm 0.19$ kpc and
$7.88\pm0.30$ kpc respectively.
