Generally, no you don't ever want to wait for raid buffs.
Example: Waiting a whole 30 seconds from 90-120. Over a 6 min:
Using on CD you get 4 uses of IR at 1.5, 3, 4.5, 6 min. 4x IR. 2x align with 120sec buffs.
Using on 120 sec you get 3 uses. 2, 4, 6 min. 3x IR. 3x align with 120 sec buffs.
(were ignoring the opener at 0 because everyone always gets that no matter what).
If you notice, you trade off TWO unbuffed IRs to get ONE with a little boost of 10% (or whatever % buff you are aligning with). 200% iR (2 uses) vs 1 use at 100%+X% where X is the buff. That's a terrible trade.
The simpler way to think about 'should I hold a skill for a buff' is as a % of the timer. Think of it this way. 9 seconds is 10% of the CD on IR. Every 9 sec you wait you are delay the NEXT IR by 10%. Lowering the effectiveness of the skill by 10%. Delaying it by 30 sec means you lost 33% of the CD so you lost 33% of an entire IR. Is that buff from waiting bigger than 33%? If the answer is yes, then wait. If no, then don't.
Practical example:
Eye buff (10% damage) just fell off. Upheaval is up. Do you wait 7.5 sec to do an Eye combo then upheaval, or just upheaval right now? Upheaval is a 30sec CD. 7.5 sec is 25% of 30 sec so waiting 'wastes' 25% of an upheaval. But waiting also gives your upheaval 10% more damage. 25%>10% so go ahead and use it without Eye. Its a damage gain.
Twist:
Same deal, but you just used maim. Do you upheaval now or wait 2.5 sec for Eye buff? 2.5sec is only 8.3% of upheavals CD so you are giving up 8.3% of an upheaval to gain 10% damage. Wait the 1 gcd for the buff. Its a damage gain to wait.
You can apply that logic to every CD in the game. Time is a resource and sitting on CDs wastes that resource.
Every moment you sit on a CD is pushing the next use farther away. Imagine just not hitting the next piece of your GCD combo for 5 sec to wait for a raid buff. That's silly. You are delaying your GCDs for a 5-10% buff? No. Just use them on cooldown. Buffs are the exact same thing just longer than 2.5 sec, but the principle is the same.