Tweak biblatex for astronomy

biblatexstyle.tex

\documentclass[12pt]{article}

\usepackage[
  backend=biber,
  bibencoding=utf-8,
  natbib,
  style=authoryear,
  maxcitenames=9,                       % use "et al" for > 9 (citations)
  maxbibnames=9,                        % use "et al" for > 9 (references)
  giveninits,                           % initialize given names
  uniquename=init,
  dashed=false,                         % don't use dash for repeated names
]{biblatex}

% Remove "p."/"pp." in citations and references
\DefineBibliographyStrings{english}{%
  page = {},
  pages = {},
}

% Use "&" instead of "and"
\let\origparencite\parencite
\renewrobustcmd{\parencite}{%
  \AtNextCite{%
  \renewcommand*{\finalnamedelim}{%
    \ifnumgreater{\value{liststop}}{2}{\finalandcomma}{}%
    \addspace\&\space}%
  }%
  \origparencite%
}
\AtBeginBibliography{%
  \renewcommand*{\finalnamedelim}{%
    \ifnumgreater{\value{liststop}}{2}{\finalandcomma}{}%
    \addspace\&\space}%
}

\DeclareNameAlias{labelname}{family-given} % in citations
\DeclareNameAlias{sortname}{family-given}  % in references

% remove "in:" before journal names in references
\renewbibmacro{in:}{}

% remove "URL:" before URLs
\DeclareFieldFormat{url}{\url{#1}}

% Remove parentheses around year
\usepackage{xpatch}
\xpatchbibmacro{date+extradate}{%
  \printtext[parens]%
}{%
  \setunit*{\addperiod\space}%
  \printtext%
}{}{}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Remaining part of file is for testing only
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\usepackage{hyperref}

\usepackage{filecontents}
\begin{filecontents*}{foobar.bib}
@Article{einstein,
  author       = {Albert Einstein and John Smith and Jane Collins and Mary Antoine},
  title        = {Zur Elektrodynamik bewegter Körper.},
  year         = 1905,
  volume       = 322,
  number       = 10,
  pages        = {891-921},
  journaltitle = {Annalen der Physik},
  doi          = {10.1002/andp.19053221004}
}

@Article{einstein2,
  author       = {Albert Einstein and John Smith and Jane Collins and Mary Antoine},
  title        = {The quick brown fox.},
  year         = 1905,
  volume       = 3,
  number       = 14,
  pages        = 15926,
  journaltitle = {American Astronomy of Societies},
  archivePrefix = {arXiv},
  eprint       = {0902.0885},
  url          = {https://google.com}
}
\end{filecontents*}

\addbibresource{foobar.bib}

\begin{document}

The quick brown fox jumps over the lazy dog.\parencite[arfarf][12345]{einstein}

Hello world.\parencite[awoo][12345]{einstein2}

\printbibliography

\end{document}