A continuación os explico como instalar python 3.x en un servidor cpanel

Actualizamos e instalamos:
yum update
yum groupinstall -y «development tools»
yum install -y zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel expat-devel

Bajamos y descomprimimos:
cd /usr/local/src
wget https://www.python.org/ftp/python/3.6.3/Python-3.6.3.tgz
tar xzf Python-3.6.3.tgz
cd Python-3.6.3

Compilamos
./configure –prefix=/usr/local/python3.6 –enable-shared LDFLAGS=»-Wl,-rpath /usr/local/lib»
make
make altinstall

Editamos /etc/profile.d/python3.6.sh with a text editor.
Y le metemos:
PATH=$PATH:/usr/local/python3.6/bin
export PATH

Editamos /etc/ld.so.conf.d/opt-python3.6.conf
Y le metemos:
/usr/local/python3.6/lib

Actualizamos:
ldconfig
source /etc/profile.d/python3.6.sh

Confirmamos:
python3.6