How many until he's top scorer of all time of the sport?
In terms of top level football, he is already top scorer of all time. Here's the list:
1. Ronaldo 783 goals
2. Pele 767 goals (or 769)
3. Romario 761 goals
4. Puskas 759 goals
5. Messi 745 goals
6. Bican 743 goals
7. Jimmy Jones 659 goals
8. Muller 640 goals
If also includes those official goals scored in regional league and youth/amateur/reserve games, Helmchen (982), Bican (948), Puskas (808) are still ahead of him. Here's the list:
1. Helmchen 982 goals
2. Bican 948 goals
3. Puskas 808 goals
4. Ronaldo 801 goals
5. Deak 794 goals
6. Romario 780 goals
7. Pele 775 goals
8. Messi 774 goals
If also include all goals scored in all unofficial games (club friendlies, unofficial amateur/reserve level football etc), obviously there were quite a few who scored well over 1000 goals, such as Tichy (1912), Bican (1812), Helmchen (1610), Puskas (1567), Muller (1483), Bene (1412), Deak (1369), Pele (1301) etc
But I don't really think those club friendlies or youth/amatuer/regional goals matters, as they are in very poor standard. To the extreme, Its just like scoring in your own backyard, or something.
So in short, it really depends on what criteria you are looking it. In terms of most relevant criteria, if we only count official goals scored in top level (excluding youth games, reserve games, amateur/regional level etc) Ronaldo is already the top scorer of all time.