As a rogue, we get the proficiency to use Hand crossbow (which is an exotic weapon). And so can a rogue use a Repeating hand crossbow (also list as an exotic weapon) without handicap? Or would we have to gain a proficiency exotic in this kind of weapon to use it?
No, it's not sufficient
(Since so many comments are arguments about whether it would make sense to allow it anyway: You are probably right! I was answering with the intent to clarify the rules, nothing prevents you from asking your GM to allow this at your table.)
"repeating" is not a modifier (trip, reach, etc. are explicitly listed as such), a Repeating Crossbow is listed as its own entry in the weapons table.
In contrast, a Composite Longbow has the following rule:
For purposes of Weapon Proficiency and similar feats, a composite longbow is treated as if it were a longbow.
A Repeating Crossbow does not have a similar rule, so I don't see why your rogue should have Proficiency. Your he would need to choose Exotic Weapon Proficiency, once for each type of exotic weapon he wants to use proficiently.
By the way, the Core Rulebook does not mention a "Repeating Hand Crossbow", just "Hand Crossbow" and "Light/Heavy Repeating Crossbow".
By RAW, it is not sufficient
As outlined by Silverclaw, the rules officially state that Repeating crossbows require Exotic Weapon Proficiency to use. However as this makes the weapon fundamentally worse than a longbow and costs additional feat to boot, I would house rule to allow it. There is some supporting evidence that this should be allowed.
The important text for Repeating Hand Crossbow
This weapon functions identically to a repeating heavy crossbow, except its damage, critical, and range values are equivalent to those of a hand crossbow instead.
The Repeating Heavy Crossbow has the following rule.
You can fire a repeating crossbow with one hand or fire a repeating crossbow in each hand in the same manner as you would a normal crossbow of the same size. However, you must fire the weapon with two hands in order to use the reloading lever, and you must use two hands to load a new case of bolts.
So yes your proficiency with a Hand Crossbow should be enough to use a Repeating Hand Crossbow. However this is a homebrew ruling and will require DM approval.