I am writing my thesis and my university requirements ask me to set the footnotes font size at 9pt. The body text size is 12pt. I tried to change the value using :
\renewcommand{\footnotesize}{(one of the 8 values)}
but looking at this table

I realized that none of the possible values would give me a font size of 9. How can I solve the problem?
Here it is the preamble:
\documentclass[a4paper,12pt]{report}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\let\up\textsuperscript
\usepackage{blindtext}
\usepackage{setspace}
\renewcommand{\baselinestretch}{1.5}
\usepackage{pslatex}
\usepackage{titlesec}
\titleformat{\chapter}
{\normalfont\fontsize{14}{14}\bfseries}{\thechapter}{1em}{}
\titleformat{\section}
{\normalfont\fontsize{13}{13}\bfseries}{\thesection}{1em}{}
\titleformat{\subsection}
{\normalfont\fontsize{12}{12}\bfseries\slshape}{\thesubsection}{1em}{}
\usepackage{amsmath, amsthm, amssymb, amsfonts}
\mathchardef\mhyphen="2D
\usepackage{fancyhdr}
\fancypagestyle{IHA-fancy-style}{%
\fancyhf{}% Clear header and footer
\fancyhead[LE,RO]{\slshape \rightmark}
\fancyhead[LO,RE]{\slshape \leftmark}
\fancyfoot[R]{\thepage}% Custom footer
\renewcommand{\headrulewidth}{0pt}% Line at the header visible
\renewcommand{\footrulewidth}{0pt}% Line at the footer visible
}
% Redefine the plain page style
\fancypagestyle{plain}{%
\fancyhf{}%
\fancyfoot[R]{\thepage}%
\renewcommand{\headrulewidth}{0pt}% Line at the header invisible
\renewcommand{\footrulewidth}{0pt}% Line at the footer visible
}
\usepackage{fancyhdr}
\pagestyle{plain}
\lhead{}
\chead{}
\rhead{}
\lfoot{}
\cfoot{}
\rfoot{\thepage}
\renewcommand{\headrulewidth}{0pt}
\renewcommand{\footrulewidth}{0pt}
\usepackage{graphicx}
\usepackage{color}
\usepackage{transparent}
\usepackage{caption}
\usepackage{enumerate}
\usepackage{url}
\usepackage{natbib}
\bibliographystyle{abbrvnat}
\setcitestyle{authoryear,open={},close={}}
\usepackage[]{tocbibind}
\usepackage{makeidx}
\usepackage{lipsum}
%\pagestyle{headings}
%\usepackage{emptypage}
\title{Epistemic Contextualism:\\ Skeptcism and Intuitions}
\author{Alessandro Rizzo\\ Department of Philosophy, Vita-Salute S.Raffaele University}

\footnotesizeat other places as well. Should the change be done there too? If not, changing the size of footnotes depends heavily on the class (and maybe footnote-related packages), so we need a MWE. – Johannes_B Jun 09 '15 at 15:16documentclassmissing ;-) MWE: -> http://www.dickimaw-books.com/latex/minexample/html/ Convenience for helpers, copy/paste/compile/ – Johannes_B Jun 09 '15 at 15:18\fontsize{14}{14}makes sense only if you don't expect chapter titles span two lines. – egreg Jun 09 '15 at 15:21