that Putin & Bibi are living in perfect harmony contrary to their wet-dreams of impending doom and confrontation.

With regard to Syria, Russia has bigger fish to fry than issues relative to Israel ... such as possible interventions by US or Turkey.

regardless of any understandings between israel and russia, it remains a
fact that russia is allied with israel's enemies.
furthermore, as a result of the obama regime's policies in the middle east,
russia is firmly entrenched militarily in syria and even in iran.
it follows that israel's present national security and strategic posture is
weaker than it was during the bush era.
yet it must be assumed that there might come a point in time when
israel will be forced to open a defencive action against the shia terror
regime's proxy hezbollah. such an action would take place regardless
of russian military presence near israel.
israel will always defend herself regardless of the enemy's allies.

stalin had purged the red army of its top officers and engineers in the thirties. the ussr was left unprepared for a war with germany.
it was the americans and the british that eventually armed the ussr with many weapons, mainly tanks, amoured vehicles and aircraft, starting 1941.
without this military aid, russia would have lost the war against the
germans.
furthermore, your claim that the americans and the british were not
involved in the war effort against nazi germany is a total lie.
the western allies liberated all of western europe. the red army
never put a foot into western europe. berlin was occupied by the red army and the western allies, namely, the united states, the brits, the french.
the red army occupied eastern european countries which the ussr kept
occupied by fiat until the collapse of the ussr.

"So far" is the only thing we know with Putin.

Putin is now in a "confidence building" phase, he has more urgent matters at hand like consolidating is power in Syria, showing to the region he can deliver.

We can't trust Putin more than we trusted USSR.
He has sultanchik Erdo to deal with in the north and Nato won't help Erdo once he invaded Syria, Nato is a defensive alliance.

Once Putin will find advantageous to challenge Israel he will do it, maybe firing some S400 ... then? What we'll do face to his thug's "so what?" posturing? Start WWW3? Push the button?

We can't trust Putin more than we trusted the USSR.