  We study the stellar, Brightest Cluster Galaxy (BCG) and intracluster medium
(ICM) masses of 14 South Pole Telescope (SPT) selected galaxy clusters with
median redshift $z=0.9$ and median mass $M_{500}=6\times10^{14}M_{\odot}$. We
estimate stellar masses for each cluster and BCG using six photometric bands
spanning the range from the ultraviolet to the near-infrared observed with the
VLT, HST and Spitzer. The ICM masses are derived from Chandra and XMM-Newton
X-ray observations, and the virial masses are derived from the SPT
Sunyaev-Zel'dovich Effect signature.
  At $z=0.9$ the BCG mass $M_{\star}^{\textrm{BCG}}$ constitutes $0.12\pm0.01$%
of the halo mass for a $6\times10^{14}M_{\odot}$ cluster, and this fraction
falls as $M_{500}^{-0.58\pm0.07}$. The cluster stellar mass function has a
characteristic mass $M_{0}=10^{11.0\pm0.1}M_{\odot}$, and the number of
galaxies per unit mass in clusters is larger than in the field by a factor
$1.65\pm0.2$. Both results are consistent with measurements on group scales and
at lower redshift. We combine our SPT sample with previously published samples
at low redshift that we correct to a common initial mass function and for
systematic differences in virial masses. We then explore mass and redshift
trends in the stellar fraction (fstar), the ICM fraction (fICM), the cold
baryon fraction (fc) and the baryon fraction (fb). At a pivot mass of
$6\times10^{14}M_{\odot}$ and redshift $z=0.9$, the characteristic values are
fstar=$1.1\pm0.1$%, fICM=$9.6\pm0.5$%, fc=$10.4\pm1.2$% and fb=$10.7\pm0.6$%.
These fractions all vary with cluster mass at high significance, indicating
that higher mass clusters have lower fstar and fc and higher fICM and fb. When
accounting for a 15% systematic virial mass uncertainty, there is no
statistically significant redshift trend at fixed mass in these baryon
fractions.
  (abridged)
