align text after formula in separate equations

I have some text following equations that are separated by paragraphs (so I can't use \intertext). I would like this text to be aligned horizontally in all of the equations in the document. Example:

\documentclass{article}
\thispagestyle{empty}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
a_i + b_i = c_i
\qquad \text{for i = 2, \dots, 9}
\end{equation*}
Then a lot of text follows.
k_i = a_i + b_i + \sqrt{\text{some stuff that messes up alignment}} \qquad \text{for i = 1, \dots, 7}
\end{document}


where I would like the for to be aligned.

This solution centers the first equation in the space taken by the second equation.

\documentclass{article}
\thispagestyle{empty}
\usepackage{mathtools}
\newsavebox{\tempbox}
\begin{document}
\savebox{\tempbox}{\displaystyle k_i = a_i + b_i + \sqrt{\text{some stuff that messes up alignment}}}
\begin{align}
\mathmakebox[\wd\tempbox][c]{a_i + b_i = c_i}
\qquad &\text{for i = 2, \dots, 9} \notag
\intertext{Then a lot of text follows.}
\usebox{\tempbox}
\qquad &\text{for i = 1, \dots, 7}
\end{align}
\end{document}


\documentclass{article}
\thispagestyle{empty}
\usepackage{amsmath}
\begin{document}
\begin{align*}
a_i + b_i &= c_i
&\qquad \text{for }i = 2, \dots, 9\\% math mode here!!!!
\intertext{
Then a lot of text follows.
\endgraf
and more
\endgraf
a third paragraph
}
k_i &= a_i + b_i + \sqrt{\text{some stuff that messes up alignment}}
&\qquad \text{for } i = 1, \dots, 7% math mode here!!!!
\end{align*}
\end{document}