Vertical Text using multirow in the Table

Here's the code:

\documentclass[twocolumn]{article}
\usepackage{tabularx}
\usepackage{array}
\usepackage{rotating}
\usepackage{lipsum}
\usepackage{multirow}
\renewcommand\tabularxcolumn[1]{>{\small}m{#1}}
\newcolumntype{Y}{>{\centering\arraybackslash}X}
\newcommand\RotText[1]{\rotatebox{90}{\parbox{3.5cm}{\centering#1}}}

%\newlength{\arrayrulewidthOriginal}
\newcommand{\Cline}[2]{%
\noalign{\global\setlength{\arrayrulewidthOriginal}{\arrayrulewidth}}%
\noalign{\global\setlength{\arrayrulewidth}{#1}}\cline{#2}%
\noalign{\global\setlength{\arrayrulewidth}{\arrayrulewidthOriginal}}}

\begin{document}

{
\setlength\tabcolsep{1pt}
\setlength\extrarowheight{1.8pt} %new code
\begin{tabularx}{\columnwidth}{|Y|l|Y|Y|Y|Y|Y|Y|Y|Y|Y|}
\cline{3-9}
\multicolumn{1}{c}{}& & &\multicolumn{6}{c|}{text}\\
\cline{4-9}
\multicolumn{1}{c}{} & & &
\multicolumn{3}{c|}{text}  & 
\multicolumn{3}{c|}{text} \\
\cline{4-9}

\multicolumn{1}{c}{}&
\multicolumn{1}{c|}{} & 
\RotText{some text} &
\RotText{Some really long text} & 
\RotText{Some really long text} & 
\RotText{Some really long text} & 
\RotText{Some really long text} & 
\RotText{Some really long text} & 
\RotText{Some really long text}  \\ \hline
%\noalign{\hrule height 1pt}


 \multirow{-2}{*}{\RotText{Text across A-E}} & A & 21 & 11 & 44 & 11 & 54 & 34 & 54 \\ \cline{2-9}
& B & 11 & 11 & 44 & 11 & 54 & 34 & 54 \\ \cline{2-9}
& C & 11 & 11 & 44 & 11 & 54 & 34 & 54 \\ \cline{2-9}
& D & 11 & 11 & 44 & 11 & 54 & 34 & 54 \\ \cline{2-9}
& E & 11 & 11 & 44 & 11 & 54 & 34 & 54 \\ \hline
\end{tabularx}
}

\end{document}

I added some extra row height because the text was too long for the available space. If your actual text is shorter you can remove the extra row height