  We present optical photometry for the afterglow of GRB 221009A, in some
respects the most extraordinary gamma-ray burst (GRB) ever observed. Good
quality in the R-band light curve is obtained, covering 0.32-19.57 days since
the Fermi-GBM trigger. We find that a weak bump emerges fromthe declining
afterglow at $t \approx 11$ days; a supernova (SN) may be responsible. We use a
smooth broken power-law and $^{56}\mathrm{Ni}$ model to fit the light curve.
The best-fitting results reveal that the SN ejected a total mass of
$M_\mathrm{ej} = 3.70 M_\odot$, a $^{56}\mathrm{Ni}$ mass of $M_\mathrm{Ni} =
0.23 M_\odot$, and a kinetic energy of $E_\mathrm{SN,K} = 2.35 \times 10^{52}
\mathrm{erg}$. We also compare GRB 221009A with other GRB-SN events based on a
GRB-associated SN sample, and find that only SN 2003lw and SN 2011kl can be
obviously revealed in the afterglow of GRB 221009A by setting these objects at
its distance. This suggests that a supernova (SN 2022xiw) is possibly obscured
by the brighter afterglow emission from GRB 221009A.
