  We present measurements of stellar populations properties of a z = 9.1
gravitationally lensed galaxy MACS1149-JD1 using deep JWST NIRISS slitless
spectroscopy as well as NIRISS and NIRCam imaging from the CAnadian NIRISS
Unbiased Cluster Survey (CANUCS). The galaxy is split into four components.
Three magnified (${\mu}$ ~ 17) star-forming components are unresolved, giving
intrinsic sizes of < 50pc. In addition, the underlying extended component
contains the bulk of the stellar mass, formed the majority of its stars ~ 50Myr
earlier than the other three components and is not the site of the most active
star formation currently. The NIRISS and NIRCam resolved photometry does not
confirm a strong Balmer break previously seen in Spitzer. The NIRISS grism
spectrum has been extracted for the entire galaxy and shows a clear continuum
and Lyman-break, with no Lyman-${\alpha}$ detected.

Astrophysics of Galaxies