Minimum recommended amplification requirements and amplifier matching

I know many here disagree with me, but I am a strong advocate of powerful amplifiers for much better dynamics and less distortion on music peaks. It does depend on the size of the room, of course.

@willemj  +1  My experience agrees with your's.  The old audio axiom that you can't have too powerful of an amplifier is true.  Your system can find itself in peril when it is underpowered and the sine wave is being clipped on musical peaks.  The only way an amp can be too powerful is if your two year old grabs your preamp volume knob and decides to engage in a lesson on clockwise turning!👶

I agree with Willem and hifiman. There's more to driving speakers than the 90dB spec, and we don't know if the stated sensitivity is rated for 8 ohms or 4 ohms.
In addition to sensitivity, the impedance curve is an important factor; how much power will be required to satisfactorily drive the load throughout the frequency range; eg, does the amp have the power to drive the bass frequencies or react to peaks and transients without clipping.

If it’s a "recommendation" and a "requirement" at the same time, I’d consider this "unusual". Typically this should be something like "recommend amplifier power", etc.

It most likely will sound "loud enough", but, with respect to the referenced speaker and amp, 3 important questions:
1.  Was it designed/voiced for a solid state or tube amp and particularly what does the impedance curve look like at the frequency extremes. 
2.  What is the dynamic range of the music you listen to?  Power requirements rise exponentially on peaks. 
3.  Do you plan to run it in triode or ultra-linear mode?