\documentclass[tikz]{standalone}
\usepackage{pgflibraryshapes}
\usetikzlibrary{backgrounds}
\usetikzlibrary{arrows}
\begin{document}
\begin{tikzpicture}[scale = 1.,font=\fontsize{8}{8}\selectfont]
\path (0.,0.) node(8_0) [draw,shape=circle,color=gray] {8};
\path (1.,0.) node(9_0) [draw,shape=circle,color=gray] {9};
\path (2.,0.) node(10_0) [draw,shape=circle,color=gray] {10};
\path (0.,1.) node(11_0) [draw,shape=circle,color=gray] {11};
\path (1.,1.) node(12_0) [draw,shape=circle,color=gray] {12};
\path (2.,1.) node(13_0) [draw,shape=circle,color=gray] {13};
\path (0.,2.) node(14_0) [draw,shape=circle,color=gray] {14};
\path (1.,2.) node(15_0) [draw,shape=circle,color=gray] {15};
\path (2.,2.) node(16_0) [draw,shape=circle,color=gray] {16};
\path
(0,0);
\draw[color=gray] (8_0) -- (9_0) -- (11_0) -- (8_0);
\draw[color=gray] (12_0) -- (14_0) -- (11_0) -- (12_0);
\draw[color=gray] (11_0) -- (9_0) -- (12_0) -- (11_0);
\draw[color=gray] (12_0) -- (10_0) -- (13_0) -- (12_0);
\draw[color=gray] (10_0) -- (12_0) -- (9_0) -- (10_0);
\draw[color=gray] (15_0) -- (13_0) -- (16_0) -- (15_0);
\draw[color=gray] (13_0) -- (15_0) -- (12_0) -- (13_0);
\draw[color=gray] (12_0) -- (15_0) -- (14_0) -- (12_0);
\end{tikzpicture}
\end{document}