-I think Saruman the White (before spell in spellbook) needs magic shield like Gandalf, if I did not saw wrong Saruman used magic shield while fighting with Ring Wraiths..
-Saruman was never a servant of Sauron like in the LOTR films, Saruman was always opponent of Sauron for ring, so Saruman of Many Colors is not a puppet..
-What about a Saruman on good side? Maybe that magic shield is a good idea for this Saruman..
Well, there are, I think, a few considerations to make
The Saruman of the Edain Mod is not the one of the Hobbit timeline, when he was the authoritative Chief of the White Council.
The Saruman of the War of the Ring is wicked and corrupted, not only by Sauron, but mainly by his Greed and Ambitions of ruling the People of Middle Earth with his superior Power and Authority, something that the Istari were expressly ordered not to do by the Valar.
He thus FAILED his mission as an Istar.
It's true, Saruman was not completely a puppet of Sauron, as the LOTR trilogy has interpreted.
But he was nonetheless deceived by Sauron, and, as for many other characters in the Ages of Arda, ended up being unwillingly controlled by him.
Saruman truly believed to have deceived Sauron and acted in secret without him realising it; but you can't just deceive Sauron, who is rightly known as the 'Deceiver', the one who deceived the Elves (Celebrimbor) in the forging of the Rings of Power, and caused the Fall of Númenor (the most powerful Kingdom at that time) with his lies.
Sauron, in fact, helped consistently the 'corruptive process' of Saruman, and literally used him as a mere shield to destroy Rohan and the People of the Western Lands of Middle Earth, or just keep them at bay for a while, preparing in the meantime the final attack of Mordor against the World.
I don't really like the idea of a magical shield for Saruman as well.
A shield like that is really suitable for Gandalf, as he is constantly journeying across Middle Earth as a Lonely Wanderer, always confronting dark and foul creatures, and thus needing to directly defend himself.
Saruman, instead, although he theoretically could have created a magical shield, has stably established in Isengard for many, many years, and his Magic is much more 'extensive' and comprehensive than Gandalf's; Saruman used his powers to corrupt Isengard, create an industry, and artificially bring to life a new race of Orcs.
Saruman relies primarily on his Army and Servants for his own defence, especially after he put all his powers in the marring of his Land, gradually and constantly losing them.
It's a quite different kind of Magic, less 'direct' than Gandalf's, but much more inclusive