looks like the epel-release-7-9.noarch.rpm is no longer current ( ERROR 404: Not Found) , need to change to EPEL 7-10 on line 1 and 3 as seen below
suggested change
sudo yum install -y wget
wget http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-10.noarch.rpm
sudo rpm -ihv epel-release-7-10.noarch.rpm
sudo yum install -y htop
thanks!!!!