  We present ALMA deep spectroscopy for a lensed galaxy at $z_{\rm spec}=8.496$
with $\log(M_{\rm star}/M_{\odot})\sim7.8$ whose optical nebular lines and
stellar continuum are detected by JWST/NIRSpec and NIRCam Early Release
Observations in SMACS0723. Our ALMA spectrum shows [OIII]88$\mu$m and
[CII]158$\mu$m line detections at $4.0\sigma$ and $4.5\sigma$, respectively.
The redshift and position of the [OIII] line coincide with those of the JWST
source, while the [CII] line is blue-shifted by 90 km s$^{-1}$ with a spatial
offset of $0.''5$ ($\approx0.5$ kpc in source plane) from the JWST source. The
NIRCam F444W image, including [OIII]$\lambda$5007 and H$\beta$ line emission,
spatially extends beyond the stellar components by a factor of $>8$. This
indicates that the $z=8.5$ galaxy has already experienced strong outflows whose
oxygen and carbon produce the extended [OIII]$\lambda$5007 and the offset [CII]
emission, which would promote ionizing photon escape and facilitate
reionization. With careful slit-loss corrections and removals of emission
spatially outside the galaxy, we evaluate the [OIII]88$\mu$m/$\lambda$5007 line
ratio, and derive the electron density $n_{\rm e}$ by photoionization modeling
to be $220^{+170}_{-100}$ cm$^{-3}$, which is comparable with those of
$z\sim2-3$ galaxies. We estimate an [OIII]88$\mu$m/[CII]158$\mu$m line ratio in
the galaxy of $>4$, as high as those of known $z\sim6-9$ galaxies. This high
[OIII]88$\mu$m/[CII]158$\mu$m line ratio is generally explained by the high
$n_{\rm e}$ as well as the low metallicity ($Z_{\rm
gas}/Z_{\odot}=0.04^{+0.02}_{-0.02}$), high ionization parameter ($\log U >
-2.27$), and low carbon-to-oxygen abundance ratio ($\log$(C/O)
$=[-0.52:-0.24]$) obtained from the JWST/NIRSpec data; further [CII] follow-up
observations will constrain the covering fraction of photodissociation regions.
