Can a society without religious guidance or a religious "code of Ethics" lead a moral life?
Yes. There have been atheist societies in human history, and it wasn't the absence of religion that made them better or worse.
Then there have been societies where religion existed, but had little say in the commonly obeyed code of Ethics.
There's also laicist nations in this day and age, and they still have perfectly normal (in the truest sense of the word) codes of Ethics.
Even when ignoring historical precedents and debating this on a purely philosophical level, I think as early as Rousseau
(Contrat Social:IV), La Mettrie or even Schopenhauer
(Parerga & Paralipomena), people made pretty convincing arguments for this.
In other words, if religion was gone would society be able to stay together?
Yes. Religion is not necessarily
the glue that keeps society together. There's many things that may supplant it. Ideology, or whatever you prefer.
I've always been stunned and awed by the supposition that religion and morality form some sort of magically unified superstructure, and that morality without religion should be supposed to be impossible.
So as a society could we still keep things together or would those who can't follow their own moral compass degrade to less than civility?
Firstly, this seems to me to be a different issue from the original question, whether religion and moral could exist independently of each other.
Secondly, I think most people don't follow their own moral compass whenever it's more convenient for them, religious or not. That's why so many religions know the concept of sin - in the sense of acting against a deity's word even though you know better.
I don't think this constitutes a degradation to less than civility. It is the common modus operandi of humanity, and if you suppose that we do currently have a certain level of civility, that constitutes pretty good evidence in favor of my statement, I think.
In fact, I think it utopian to assume that anyone could ever fully follow their own moral compass.
The only law I've broken in my adult is a traffic law but, who doesn't have at least one speeding ticket?
Meeeee! I'm one of those drivers everyone hates; I click in the speed control at exactly the designated limit and then just tool along the freeway.