As says in the title, you cannot obtain items from creative, the server will kick you and output an exception to the console.
Here is the exception:
14:12:24 [WARNING] Failed to handle packet: java.lang.IndexOutOfBoundsException: Index: 46, Size: 45
java.lang.IndexOutOfBoundsException: Index: 46, Size: 45
at java.util.ArrayList.rangeCheck(ArrayList.java:571)
at java.util.ArrayList.get(ArrayList.java:349)
at net.minecraft.server.Container.a(SourceFile:128)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:997)
at net.minecraft.server.Packet102WindowClick.handle(SourceFile:28)
at net.minecraft.server.NetworkManager.b(NetworkManager.java:231)
at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:101)
at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:543)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:441)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:465)