That's 30W but with no reference to impedance, frequency, THD or whether it's RMS or not.
30Wpc R.M.S. in to 8 Ohms at 20Hz-20kHz, 0.05% THD is a repectable power level. Most good budget British Hi-fi amps from the 80s and 90s were in that range, and with their large toroidal transformers and decent output transistors they could generate a fairly healthy curent swing so did just find with the less efficient bookshelf speakers they were typically paired with. This is because the power measurement was done in a way that left a lot in reserve.
The N9 is a decent product, but the marketing men like to have big numbers to shout about. Measuring at 6 Ohms, and a higher THD (1%), possibly 1 channel driven rather than 2, most likely peak power rather than RMS, and at 1kHz where the amp is most efficient, all makes the final result look good on paper, but in real world situation it'll translate to something around 15-20W per channel measure in Hi-fi terms.
You could still have some fun with that as long as you weren't after room shaking volume.
If the dealer has an N9 or Marantz equivalent in stock then deffo arrange a listening session. Or take the N9 down.