  We present a photometric study of the resolved stellar populations in And IX,
the closest satellite to the M31, a metal-poor and low-mass dwarf spheroidal
galaxy. We estimate a distance modulus of $24.56_{-0.15}^{+0.05}$ mag based on
the tip of the red giant branch (TRGB). By probing the variability of
asymptotic giant branch stars (AGB), we study the star formation history of And
IX. We identified 50 long period variables (LPVs) in And IX using the Isaac
Newton Telescope (INT) in two filters, Sloan $i'$ and Harris $V$. In this
study, we selected LPVs within two half-light radii with amplitudes in the
range of 0.2-2.20 mag. It is found that the peak of star formation reaches
$\sim$ $8.2\pm3.1\times10^{-4}$ M_sun yr$^{-1}$ at $\approx 6$ Gyr ago. Our
findings suggest an outside-in galaxy formation scenario for And IX with a
quenching occurring $3.65_{-1.52}^{+0.13}$ Gyr ago with the SFR in the order of
$2.0\times10^{-4}$ M_sun yr$^{-1}$ at redshift < $0.5$. We calculate the total
stellar mass by integrating the star formation rate (SFR) within two half-light
radii $\sim$ $3.0\times10^5$ M_sun. By employing the spectral energy
distribution (SED) fitting for observed LPVs in And IX, we evaluate the
mass-loss rate in the range of $10^{-7}$ $\leq$ $\dot{M}$ $\leq$ $10^{-5}$
M_sun yr$^{-1}$. Finally, we show that the total mass deposition to the
interstellar medium (ISM) is $\sim$ $2.4\times10^{-4}$ M_sun yr$^{-1}$ from the
C- and O-rich type of dust-enshrouded LPVs. The ratio of the total mass
returned to the ISM by LPVs to the total stellar mass is $\sim
8.0\times10^{-10}$ yr$^{-1}$, and so at this rate, it would take $\sim$ 1 Gyr
to reproduce this galaxy
