You can use the environment strip ( package cuted) to insert wide material into the two-column document at the desired location.
Obviously it doesn't support floats, so you have to use \captionof{figure}{<text>} to insert the caption (package caption).

% !TeX TS-program = pdflatex
\documentclass[conference]{IEEEtran}
\usepackage{graphicx, array, blindtext}
\usepackage{kantlipsum} % only for dummy text
\usepackage[format=hang]{caption} % captionof <<<<<
\usepackage{cuted} % wide content <<<<
\begin{document}
1. \kant[1]
\begin{strip} % start wide material
\centering
\begin{tabular}{c c c}
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\end{tabular}
\captionsetup{width=0.8\linewidth}
\captionof{figure}{ Experiments Results and Polygons Experiments Results and Polygon Experiments Results and Polygon}\label{fig:exp}
\end{strip} % end wide material
2. \kant[2]
\end{document}
UPDATE after follow-up question: long figure does not fit in the page.

The tabular does not break across pages. Put the figure at the beginning of a new page or split the tabular in two, as the following example.
% !TeX TS-program = pdflatex
\documentclass[conference]{IEEEtran}
\usepackage{graphicx, array, blindtext}
\usepackage{kantlipsum} % only for dummy text
\usepackage[format=hang]{caption} % captionof <<<<<
\usepackage{cuted} % wide content <<<<
\begin{document}
1. \kant[1-4]
\begin{strip} % start wide material
\centering
\begin{tabular}{c c c}
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\end{tabular}
\captionsetup{width=0.8\linewidth}
\captionof{figure}{(a) Experiments Results and Polygons Experiments Results and Polygon Experiments Results and Polygon \emph{(cont. in next page)} }\label{fig:exp1}
\addtocounter{figure}{-1} %reset counter
\begin{tabular}{c c c}
\includegraphics[scale =0.25]{example-image-a}&
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\includegraphics[scale =0.25]{example-image-a} &
\includegraphics[scale =0.25]{example-image-b} &
\includegraphics[scale =0.25]{example-image-c}\\
\end{tabular}
\captionsetup{width=0.8\linewidth}
\captionof{figure}{(b) Experiments Results and Polygons Experiments Results and Polygon Experiments Results and Polygon}\label{fig:exp2}
\end{strip} % end wide material
2. \kant[2-6]
\end{document}