When I start playing a new game that has some kind of RPG style talent tree, I always get stressed over it. Stupid decisions you make early on in the game when you are unfamiliar with everything can end up costing you down the line. Since Assassins Creed Syndicate contains a skill tree system, it is worth knowing if all skills can be upgraded in a single playthrough.
The good news is Yes you can. There are 10 levels in the game which will grant you enough skill points to unlock all of the skills in the game. How you decide to prioritize them is up to you, but there is no need to worry about which ones you use as you will eventually be able to unlock them all once you get to a high enough level.