Its wired wrong for driving speakers. As-is it could only deliver about 60mW per channel, due to the 3.3V Vcc to the LM4864, and the single-ended load connection, and as Benta pointed out, with a low impedance load at lower audio frequencies there is an additional voltage drop across the 10uF output coupling capacitors, further limiting its output power.
Even if you wired in 8 ohm speakers direct to each LM4864's Vo1 and Vo2 pins, so they operate with a bridge-tied load as intended, following the
datasheet's Figure 1. Typical Audio Amplifier Application Circuit, it would only deliver about 250mW, so would be pretty quiet even assuming you use a reasonably large high efficiency speaker. Raising Vcc to 5V would help significantly, but either you'd need to feed the Si4703 tuner with 3.3V separately, or at least separate out its VIO pin and feed that 3.3V, so depending on the FM Click's track layout, that may not be possible.