  Several studies have detected Lyman-alpha (Ly$\alpha$) from bright
($M_\mathrm{UV}\lesssim-21.5$) galaxies during the early stages of reionization
despite the significantly neutral intergalactic medium. To explain these
detections, it has been suggested that $z>7$ Ly$\alpha$ emitters (LAEs) inhabit
physical Mpc (pMpc)-scale ionized regions powered by overdensities of faint
galaxies, but systematic searches for these overdensities near LAEs have been
challenging. Here, we use CEERS JWST/NIRCam imaging to search for large-scale
galaxy overdensities near two very UV-bright, $z=8.7$ LAEs in the EGS field. We
colour select 27 $z=8.4-9.1$ candidates, including the one LAE in the footprint
(EGSY8p7). From SED models, we infer moderately faint UV luminosities
($-21.2\lesssim{M_\mathrm{UV}}\lesssim -19.1$) and stellar masses of
$M_*\approx10^{7.5-8.8}$ M$_\odot$. All are efficient ionizing agents
($\xi_{\mathrm{ion}}^{*}\approx10^{25.5-26.0}$ Hz erg$^{-1}$) and are generally
morphologically simple with only one compact ($r_e\lesssim140$ to $\sim650$ pc)
star-forming component. 13 candidates lie within 5 arcmin of EGSY8p7, leading
to a factor-of-four galaxy overdensity at $\lesssim 5$ arcmin ($\sim 1.4$
projected pMpc at $z\sim8.7$) separations from EGSY8p7. Separations of $10-15$
arcmin ($\sim2.7-4.1$ projected pMpc) are consistent with an average field. The
spatial distribution of our sample may qualitatively suggest an $R\geq2$ pMpc
ionized bubble encompassing both LAEs in EGS, which is theoretically unexpected
but may be possible for a galaxy population $4\times$ more numerous than the
average to create with moderate escape fractions ($f_\mathrm{esc}\gtrsim0.15$)
over long times ($\gtrsim200$ Myr). Upcoming spectroscopic follow-up will
characterize the size of any ionized bubble that may exist and the properties
of the galaxies powering such a bubble.
