At that time of night, the only practical option is an expensive taxi ride.
Wavre isn't well situated as a holiday base because, although it is quite close to Brussels, it isn't on a direct railway line. There are though express buses at certain times of day.
I suggest in future that you look into connections BEFORE booking flights, because arriving at CRL at 23:00 hrs, not only is there no way of getting from Charleroi Airport to Wavre by the cheapest method, but there is no method of getting there at all (on the same day) other than by taxi/private transfer.
The last train to Ottignies from Charleroi-Sud station departs at 21:55; and the last train from Bruxelles-Midi, at 22:33; so even if you were to take the Brussels City Shuttle (€14 per person) that goes to Bruxelles-Midi (1 hr), you would have to take a taxi from Brussels to Wavre - or stay overnight in Brussels and continue the next day.
I would therefore suggest you spend the night in Charleroi, whether at a hotel near the airport or near the station (where the Ibis Hotel is right next to the station).
Doing this, you could take the cheapest route the following day which, if you return to CRL from an airport hotel, is by local (TEC) bus A from CRL to Charleroi-Sud station and train from there to BIERGES-WALIBI (closer to your hotel than Wavre station), which costs €11.50 per person (aged 12+ - children aged up to 11 travel free with at least 1 paying "adult") purchasing a combi ticket from the machine next to the bus stop outside exit 2 at the airport. This ticket will cover the whole journey on bus plus train.
TEC bus A departs at 03 and 33 mins past each hour and takes 20 mins to the station. Trains to Ottignies depart Charleroi-Sud at 55 mins past each hour and it takes 1h04 to the station Bierges(-Walibi), which is the stop before Wavre, changing in Ottignies; and to Namur on the hour, taking 1h29 changing in both Namur and Ottignies, so it would be best to take the h:03 bus and h:55 train.
If staying in Charleroi itself, you would just take the train, which costs €6.50 per adult (12+) to Bierges-Walibi.
You can see from the map on your hotel's website (http://www.leonardo-hotels.com/belgium-hotels/wavre-hotels/leonardo-hotel-wavre/directions) where the hotel is in relation to the station (blue train symbol).
Thanks for the information