Yes, this Common Fig (Ficus carica) could be pruned to a single trunk. Of course any of the present trunks, if selected, will have a distinct lean. This may be ameliorated by subsequent pruning, though it will never go away completely. Conversely you could train and stake a new basal shoot to grow upright. There are several currently at the base of the tree.
Any of these pruning methods will significantly reduce fruit production for at least a few years. Even longer if additional pruning is done to keep the plant narrow.
If this pruning is desired for space or aesthetic reasons, do proceed. However if crop yield is paramount consider maintaining a wide multi-trunk form.